Linux Mint 22.1 - o64-gcc: Undefined symbols for architecture x86_64

[ds2k5]

Hello,
did build o64-gcc on Linux Mint 22.1.

Wanna build binary for MacOS with Rust and fltk

What I did wrong at build the compiler ?

At compile process got this Error:

error: linking with `/home/developer/osxcross/target/bin/o64-gcc` failed: exit status: 1
  |
  = note:  "/home/developer/osxcross/target/bin/o64-gcc" "/tmp/rustcaK3Nr0/symbols.o" "<1 object files omitted>" "/tmp/rustcaK3Nr0/{libfltk_sys-2858258a1dabde8d.rlib}.rlib" "<sysroot>/lib/rustlib/x86_64-apple-darwin/lib/{libcompiler_builtins-*}.rlib" "-framework" "CoreFoundation" "-framework" "Carbon" "-framework" "Cocoa" "-framework" "ApplicationServices" "-lc++abi" "-lSystem" "-lc" "-lm" "-arch" "x86_64" "-mmacosx-version-min=11.3.0" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/build" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/build/Release" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib64" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib/Release" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib64/Release" "-o" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/deps/fltkmenu-40eb6784cc053e76" "-Wl,-dead_strip" "-nodefaultlibs"
  = note: some arguments are omitted. use `--verbose` to show all linker arguments
  = note: ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/build'
          ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/build/Release'
          ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib64'
          ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib/Release'
          ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib64/Release'
          Undefined symbols for architecture x86_64:
            "_OBJC_CLASS_$_UTType", referenced from:
                objc-class-ref in libfltk_sys-28
58258a1dabde8d.rlib(Fl_Native_File_Chooser_MAC.mm.o)
          ld: symbol(s) not found for architecture x86_64
          

error: could not compile `fltkmenu` (bin "fltkmenu") due to 1 previous error

/tmp$ /home/developer/osxcross/target/bin/o64-g++ hello_world.cc -o hello_world_darwin_x86_64

x86_64-apple-darwin20.4-g++: fatal error: cannot execute 'cc1plus': posix_spawnp: No such file or directory
compilation terminated.

/tmp$ /home/developer/osxcross/target/bin/o64-gcc hello_world.c -o hello_world_darwin_x86_64
x86_64-apple-darwin20.4-gcc: fatal error: cannot execute 'cc1': posix_spawnp: No such file or directory

$ /home/developer/osxcross/target/bin/o64-gcc --version

x86_64-apple-darwin20.4-gcc (GCC) 15.1.0
Copyright (C) 2025 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

/home/developer/osxcross/target/bin/o64-g++ --version
x86_64-apple-darwin20.4-g++ (GCC) 15.1.0
Copyright (C) 2025 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[MoAlyousef]

Hell @ds2k5

Rust by default targets the 11.0 sdk, in which fltk tries to link UniformTypeIdentifiers framework.
Your sdk seems to be targeting the 10.x macos sdk.
To build your project, you can try setting the deployment target to something lower:

export MACOSX_DEPLOYMENT_TARGET=10.15
# then run the build

[ds2k5]

Hello @MoAlyousef

Thank you but....had no success

**$ export MACOSX_DEPLOYMENT_TARGET=10.15

$ cargo build --target x86_64-apple-darwin --release**

   Compiling fltkmenu v0.1.0 (/home/developer/rust/fltkmenu)
error: linking with `/home/developer/osxcross/target/bin/o64-gcc` failed: exit status: 1
  |
  = note:  "/home/developer/osxcross/target/bin/o64-gcc" "/tmp/rustcs0YyUg/symbols.o" "<1 object files omitted>" "/tmp/rustcs0YyUg/{libfltk_sys-2858258a1dabde8d.rlib}.rlib" "<sysroot>/lib/rustlib/x86_64-apple-darwin/lib/{libcompiler_builtins-*}.rlib" "-framework" "CoreFoundation" "-framework" "Carbon" "-framework" "Cocoa" "-framework" "ApplicationServices" "-lc++abi" "-lSystem" "-lc" "-lm" "-arch" "x86_64" "-mmacosx-version-min=10.15.0" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/build" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/build/Release" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib64" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib/Release" "-L" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib64/Release" "-o" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/deps/fltkmenu-40eb6784cc053e76" "-Wl,-dead_strip" "-nodefaultlibs"
  = note: some arguments are omitted. use `--verbose` to show all linker arguments
  = note: ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/build'
          ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/build/Release'
          ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib64'
          ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib/Release'
          ld: warning: directory not found for option '-L/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-23b6b7c39d037c61/out/lib64/Release'
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(cfl_window.cpp.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(cfl_image.cpp.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(cfl_menu.cpp.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(cfl.cpp.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(cfl_widget.cpp.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(cfl_dialog.cpp.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Widget.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(cfl_lock.cpp.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_ask.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_contrast.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_color.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_file_dir.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Color_Chooser.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_MacOS_Sys_Menu_Bar.mm.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_draw_pixmap.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_images_core.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_System_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_oval_box.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_rounded_box.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_gtk.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_File_Icon.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_shadow_box.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_diamond_box.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Multi_Label.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_gleam.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_round_box.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_engraved_label.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_plastic.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Menu_Bar.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_BMP_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_File_Icon2.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_GIF_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_ICO_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Menu_add.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_PNG_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_PNM_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_SVG_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_XBM_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_XPM_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_JPEG_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Help_Dialog.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Menu_Button.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Menu_Window.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Tiled_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_File_Chooser2.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_File_Chooser.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Shared_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Sys_Menu_Bar.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Double_Window.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Single_Window.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Anim_GIF_Image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Overlay_Window.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Native_File_Chooser.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Native_File_Chooser_MAC.mm.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_get_system_colors.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(screen_xywh.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_add_idle.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_boxtype.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_own_colormap.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_compose.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_lock.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_grab.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_visual.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_set_font.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Group.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Menu_.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Menu_global.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Choice.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Pixmap.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Tooltip.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Window.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Window_fullscreen.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_cursor.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_arg.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Window_hotspot.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Window_iconize.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Menu.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_labeltype.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Bitmap.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(cfl_new.cpp.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(cfl_nswindow.m.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Graphics_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Graphics_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_cocoa.mm.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Cocoa_Window_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_draw.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_draw_arrow.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_read_image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(filename_ext.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_shortcut.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Image_Surface.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(filename_list.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(filename_isdir.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(filename_match.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(filename_expand.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(filename_absolute.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_oxy.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(print_button.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_font.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Browser.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Message.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Timeout.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Browser_.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Valuator.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Help_View.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_File_Input.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Preferences.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Value_Input.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Check_Button.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_File_Browser.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Image_Reader.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Device.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Return_Button.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Screen_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_macOS_platform_init.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_encoding_latin1.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_encoding_mac_roman.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Tree_Prefs.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Window_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Widget_Surface.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_vertex.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_rect.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_arc.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_curve.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Cocoa_Screen_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Copy_Surface.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Darwin_System_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_get_key_mac.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Graphics_Driver_image.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Graphics_Driver_vertex.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Graphics_Driver_rect.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Graphics_Driver_line_style.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Graphics_Driver_font.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Graphics_Driver_arci.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Graphics_Driver_color.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Copy_Surface_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_abort.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Box.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Tile.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Input.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Button.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Input_.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_utf8.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(flstring.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(numericsort.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_string_functions.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(png.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngread.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngerror.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngget.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngrtran.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngtrans.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngrio.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(gzclose.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(gzlib.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(gzread.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(inflate.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdapimin.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdmaster.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdatasrc.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdapistd.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdmarker.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jerror.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(nanosvg.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(is_spacing.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(case.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_open_uri.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(fl_symbols.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Printer.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Scrollbar.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Int_Vector.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Text_Editor.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Light_Button.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Cocoa_Printer_Driver.mm.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Posix_System_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Quartz_Image_Surface_Driver.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Slider.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_String.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Paged_Device.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(vsnprintf.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngmem.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngrutil.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngwrite.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngwutil.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngset.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(adler32.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(crc32.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(gzwrite.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(inffast.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(inftrees.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(zutil.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jutils.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jquant1.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jquant2.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdarith.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdcolor.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdcoefct.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdmainct.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdpostct.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdhuff.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdinput.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jddctmgr.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jmemmgr.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdmerge.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jdsample.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jcomapi.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Text_Display.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(filename_setext.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(Fl_Text_Buffer.cxx.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngwtran.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(pngwio.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(deflate.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jaricom.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jmemnobs.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jidctint.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jidctflt.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(jidctfst.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          ld: warning: object file (/tmp/rustcs0YyUg/libfltk_sys-2858258a1dabde8d.rlib(trees.c.o)) was built for newer macOS version (11.0) than being linked (10.15)
          Undefined symbols for architecture x86_64:
            "_OBJC_CLASS_$_UTType", referenced from:
                objc-class-ref in libfltk_sys-2858258a1dabde8d.rlib(Fl_Native_File_Chooser_MAC.mm.o)
          ld: symbol(s) not found for architecture x86_64
          

error: could not compile `fltkmenu` (bin "fltkmenu") due to 1 previous error

SDK_VERSION=10.15 ./build.sh

Given SDK does not contain libc++ headers (-stdlib=libc++ test may fail)
You may want to re-package your SDK using 'tools/gen_sdk_package.sh' on macOS

testing x86_64-apple-darwin19-clang++ -stdlib=libc++ -std=c++11 ... failed (ignored)

testing x86_64h-apple-darwin19-clang ... osxcross: error: cannot find libc++ headers
osxcross: error: while detecting target
failed (ignored)
testing x86_64h-apple-darwin19-clang++ ... osxcross: error: cannot find libc++ headers
osxcross: error: while detecting target
failed (ignored)

testing x86_64-apple-darwin19-clang ... osxcross: error: cannot find libc++ headers
osxcross: error: while detecting target

exiting with abnormal exit code (1)
run 'OCDEBUG=1 ./build.sh' to enable debug messages

[MoAlyousef]

What version of fltk-rs?
Also you might better be served with a SDK_VERSION=11.0 if the 10.15 doesn't contain libc++ headers.

[ds2k5]

What version of fltk-rs?

1.5.9

Cargo.toml

[package]
name = "fltkmenu"
version = "0.1.0"
edition = "2024"

[dependencies]
compile-time = "0.2.0"
current_platform = "0.2.0"
fltk = { version = "^1.5.9", features = ["fltk-bundled"] }
gettext-ng = "0.4.1"
sys-locale = "0.3.2"

[profile.release]
opt-level = 'z'     # Optimize for size
lto = true          # Enable link-time optimization
codegen-units = 1   # Reduce number of codegen units to increase optimizations
panic = 'abort'     # Abort on panic
strip = true        # Strip symbols from binary*

[MoAlyousef]

You should remove the fltk-bundled feature since the bundle is built for the 11.0 sdk by default. Otherwise you should package a more recent sdk.

[ds2k5]

thanks if I do this then:

Cargo.toml

[package]
name = "fltkmenu"
version = "0.1.0"
edition = "2024"

[dependencies]
compile-time = "0.2.0"
current_platform = "0.2.0"
fltk = "1.5.9"
gettext-ng = "0.4.1"
sys-locale = "0.3.2"

[profile.release]
opt-level = 'z'     # Optimize for size
lto = true          # Enable link-time optimization
codegen-units = 1   # Reduce number of codegen units to increase optimizations
panic = 'abort'     # Abort on panic
strip = true        # Strip symbols from binary*

export MACOSX_DEPLOYMENT_TARGET=10.15
cargo build --target x86_64-apple-darwin --release

-- Check for working C compiler: /home/developer/osxcross/target/bin/o64-gcc - broken
  -- Configuring incomplete, errors occurred!

  --- stderr
  CMake Error at /usr/share/cmake-3.28/Modules/CMakeTestCCompiler.cmake:67 (message):
    The C compiler

      "/home/developer/osxcross/target/bin/o64-gcc"

    is not able to compile a simple test program.

    It fails with the following output:

      Change Dir: '/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out/build/CMakeFiles/CMakeScratch/TryCompile-sY00th'
      
      Run Build Command(s): /usr/bin/cmake -E env VERBOSE=1 /usr/bin/gmake -f Makefile cmTC_47f22/fast
      /usr/bin/gmake  -f CMakeFiles/cmTC_47f22.dir/build.make CMakeFiles/cmTC_47f22.dir/build
      gmake[1]: Entering directory '/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out/build/CMakeFiles/CMakeScratch/TryCompile-sY00th'
      Building C object CMakeFiles/cmTC_47f22.dir/testCCompiler.c.o
      /home/developer/osxcross/target/bin/o64-gcc   -ffunction-sections -fdata-sections -fPIC -m64 -arch x86_64 -mmacosx-version-min=10.15  -arch x86_64 -o CMakeFiles/cmTC_47f22.dir/testCCompiler.c.o -c /home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out/build/CMakeFiles/CMakeScratch/TryCompile-sY00th/testCCompiler.c
      x86_64-apple-darwin20.4-gcc: fatal error: cannot execute 'cc1': posix_spawnp: No such file or directory
      compilation terminated.
      gmake[1]: *** [CMakeFiles/cmTC_47f22.dir/build.make:78: CMakeFiles/cmTC_47f22.dir/testCCompiler.c.o] Error 1
      gmake[1]: Leaving directory '/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out/build/CMakeFiles/CMakeScratch/TryCompile-sY00th'
      gmake: *** [Makefile:127: cmTC_47f22/fast] Error 2
      
      

    

    CMake will not be able to correctly generate this project.
  Call Stack (most recent call first):
    CMakeLists.txt:4 (project)



  thread 'main' panicked at /home/developer/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/cmake-0.1.54/src/lib.rs:1119:5:

  command did not execute successfully, got: exit status: 1

  build script failed, must exit now
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...

[MoAlyousef]

Does using clang instead of gcc work?

[ds2k5]

o64-clang insted of o64-gcc

hope did understand right and setup the ~/.cargo/config.toml right

target.x86_64-apple-darwin]
linker = "/home/developer/osxcross/target/bin/o64-clang"
ar = "/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang"

  CMAKE_TOOLCHAIN_FILE_x86_64-apple-darwin = None
  CMAKE_TOOLCHAIN_FILE_x86_64_apple_darwin = None
  TARGET_CMAKE_TOOLCHAIN_FILE = None
  CMAKE_TOOLCHAIN_FILE = None
  CMAKE_GENERATOR_x86_64-apple-darwin = None
  CMAKE_GENERATOR_x86_64_apple_darwin = None
  TARGET_CMAKE_GENERATOR = None
  CMAKE_GENERATOR = None
  CMAKE_PREFIX_PATH_x86_64-apple-darwin = None
  CMAKE_PREFIX_PATH_x86_64_apple_darwin = None
  TARGET_CMAKE_PREFIX_PATH = None
  CMAKE_PREFIX_PATH = None
  CMAKE_x86_64-apple-darwin = None
  CMAKE_x86_64_apple_darwin = None
  TARGET_CMAKE = None
  CMAKE = None
  running: cd "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out/build" && CMAKE_PREFIX_PATH="" LC_ALL="C" "cmake" "/home/developer/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/fltk-sys-1.5.9/cfltk" "-DFLTK_USE_SYSTEM_LIBPNG=OFF" "-DFLTK_USE_SYSTEM_LIBJPEG=OFF" "-DFLTK_USE_SYSTEM_ZLIB=OFF" "-DCFLTK_LINK_IMAGES=ON" "-DOpenGL_GL_PREFERENCE=GLVND" "-DFLTK_BUILD_GL=OFF" "-DCFLTK_USE_OPENGL=OFF" "-DCMAKE_OSX_DEPLOYMENT_TARGET=10.15" "-DCMAKE_OSX_SYSROOT=macosx" "-DCMAKE_OSX_ARCHITECTURES=x86_64" "-DCMAKE_EXPORT_COMPILE_COMMANDS=ON" "-DCFLTK_CARGO_BUILD=ON" "-DFLTK_BUILD_EXAMPLES=OFF" "-DFLTK_BUILD_TEST=OFF" "-DFLTK_BUILD_FLUID=OFF" "-DFLTK_BUILD_FLTK_OPTIONS=OFF" "-DFLTK_OPTION_LARGE_FILE=ON" "-DFLTK_BUILD_HTML_DOCS=OFF" "-DFLTK_BUILD_PDF_DOCS=OFF" "-DCMAKE_SYSTEM_NAME=Darwin" "-DCMAKE_SYSTEM_PROCESSOR=x86_64" "-DCMAKE_INSTALL_PREFIX=/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out" "-DCMAKE_C_FLAGS= -ffunction-sections -fdata-sections -fPIC -m64 -arch x86_64 -mmacosx-version-min=10.15" "-DCMAKE_C_COMPILER=/usr/bin/cc" "-DCMAKE_CXX_FLAGS= -ffunction-sections -fdata-sections -fPIC -m64 -arch x86_64 -mmacosx-version-min=10.15" "-DCMAKE_CXX_COMPILER=/usr/bin/c++" "-DCMAKE_ASM_FLAGS= -ffunction-sections -fdata-sections -fPIC -m64 -arch x86_64 -mmacosx-version-min=10.15" "-DCMAKE_ASM_COMPILER=/usr/bin/cc" "-DCMAKE_BUILD_TYPE=MinSizeRel"
  -- The C compiler identification is GNU 13.3.0
  -- The CXX compiler identification is GNU 13.3.0
  -- Checking whether C compiler has -isysroot
  -- Checking whether C compiler has -isysroot - yes
  -- Checking whether C compiler supports OSX deployment target flag
  -- Checking whether C compiler supports OSX deployment target flag - no
  -- Detecting C compiler ABI info
  -- Detecting C compiler ABI info - failed
  -- Check for working C compiler: /usr/bin/cc
  -- Check for working C compiler: /usr/bin/cc - broken
  -- Configuring incomplete, errors occurred!

  --- stderr
  CMake Error at /usr/share/cmake-3.28/Modules/CMakeTestCCompiler.cmake:67 (message):
    The C compiler

      "/usr/bin/cc"

    is not able to compile a simple test program.

    It fails with the following output:

      Change Dir: '/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out/build/CMakeFiles/CMakeScratch/TryCompile-epqHFk'
      
      Run Build Command(s): /usr/bin/cmake -E env VERBOSE=1 /usr/bin/gmake -f Makefile cmTC_d2627/fast
      /usr/bin/gmake  -f CMakeFiles/cmTC_d2627.dir/build.make CMakeFiles/cmTC_d2627.dir/build
      gmake[1]: Entering directory '/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out/build/CMakeFiles/CMakeScratch/TryCompile-epqHFk'
      Building C object CMakeFiles/cmTC_d2627.dir/testCCompiler.c.o
      /usr/bin/cc   -ffunction-sections -fdata-sections -fPIC -m64 -arch x86_64 -mmacosx-version-min=10.15  -arch x86_64 -isysroot macosx -o CMakeFiles/cmTC_d2627.dir/testCCompiler.c.o -c /home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out/build/CMakeFiles/CMakeScratch/TryCompile-epqHFk/testCCompiler.c
      cc: error: unrecognized command-line option '-arch'
      cc: error: unrecognized command-line option '-mmacosx-version-min=10.15'
      cc: error: unrecognized command-line option '-arch'
      gmake[1]: *** [CMakeFiles/cmTC_d2627.dir/build.make:78: CMakeFiles/cmTC_d2627.dir/testCCompiler.c.o] Error 1
      gmake[1]: Leaving directory '/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/release/build/fltk-sys-66f7ced2148ca677/out/build/CMakeFiles/CMakeScratch/TryCompile-epqHFk'
      gmake: *** [Makefile:127: cmTC_d2627/fast] Error 2
      
      

    

    CMake will not be able to correctly generate this project.
  Call Stack (most recent call first):
    CMakeLists.txt:4 (project)



  thread 'main' panicked at /home/developer/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/cmake-0.1.54/src/lib.rs:1119:5:

  command did not execute successfully, got: exit status: 1

  build script failed, must exit now
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...

[MoAlyousef]

You would have to set the CC and CXX environment variables prior to invoking cargo:

CC=/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang CXX=/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang MACOSX_DEPLOYMENT_TARGET=10.15 cargo build —target=x86_64-apple-darwin

You should also be able to export these env variables.

[ds2k5]

CC=/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang CXX=/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang MACOSX_DEPLOYMENT_TARGET=10.15 cargo build —target=x86_64-apple-darwin

   Compiling encoding_index_tests v0.1.4
   Compiling shlex v1.3.0
   Compiling crossbeam-utils v0.8.21
   Compiling proc-macro2 v1.0.95
   Compiling semver v1.0.26
   Compiling unicode-ident v1.0.18
   Compiling powerfmt v0.2.0
   Compiling paste v1.0.15
   Compiling time-core v0.1.4
   Compiling num-conv v0.1.0
   Compiling cc v1.2.23
   Compiling deranged v0.4.0
   Compiling encoding-index-simpchinese v1.20141219.5
   Compiling time-macros v0.2.22
   Compiling encoding-index-singlebyte v1.20141219.5
   Compiling encoding-index-korean v1.20141219.5
   Compiling encoding-index-tradchinese v1.20141219.5
   Compiling encoding-index-japanese v1.20141219.5
   Compiling itoa v1.0.15
   Compiling current_platform v0.2.0
   Compiling rustc_version v0.4.1
   Compiling encoding v0.2.33
   Compiling crossbeam-channel v0.5.15
   Compiling quote v1.0.40
   Compiling cmake v0.1.54
   Compiling bitflags v2.9.1
   Compiling ttf-parser v0.25.1
   Compiling once_cell v1.21.3
   Compiling byteorder v1.5.0
   Compiling sys-locale v0.3.2
   Compiling gettext-ng v0.4.1
   Compiling fltk-sys v1.5.9
   Compiling time v0.3.41
warning: fltk-sys@1.5.9: Compiler family detection failed due to error: ToolExecError: command did not execute successfully (status code exit status: 1): "/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang" "-E" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/17340652778166554238detect_compiler_family.c"
warning: fltk-sys@1.5.9: osxcross: error: cannot find libc++ headers
warning: fltk-sys@1.5.9: osxcross: error: while detecting target
warning: fltk-sys@1.5.9: Compiler family detection failed due to error: ToolExecError: command did not execute successfully (status code exit status: 1): "/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang" "-E" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/17287014108017272515detect_compiler_family.c"
warning: fltk-sys@1.5.9: osxcross: error: cannot find libc++ headers
warning: fltk-sys@1.5.9: osxcross: error: while detecting target
warning: fltk-sys@1.5.9: Compiler family detection failed due to error: ToolExecError: command did not execute successfully (status code exit status: 1): "/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang" "-E" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/900956184758601671detect_compiler_family.c"
warning: fltk-sys@1.5.9: osxcross: error: cannot find libc++ headers
warning: fltk-sys@1.5.9: osxcross: error: while detecting target
error: failed to run custom build command for `fltk-sys v1.5.9`

Caused by:
  process didn't exit successfully: `/home/developer/rust/fltkmenu/target/debug/build/fltk-sys-14535a31e491da30/build-script-main` (exit status: 101)
  --- stdout
  cargo:rerun-if-changed=build
  cargo:rerun-if-env-changed=CC
  cargo:rerun-if-env-changed=CXX
  cargo:rerun-if-env-changed=CFLTK_TOOLCHAIN
  cargo:rerun-if-env-changed=PKG_CONFIG_PATH
  cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR
  cargo:rerun-if-env-changed=CFLTK_WAYLAND_ONLY
  cargo:rerun-if-env-changed=CFLTK_GENERATE_BUNDLE_DIR
  cargo:rerun-if-changed=cfltk/CMakeLists.txt
  cargo:rerun-if-changed=cfltk/fltk.patch
  cargo:rerun-if-changed=cfltk/include
  cargo:rerun-if-changed=cfltk/src
  cargo:rerun-if-env-changed=SDKROOT
  CMAKE_TOOLCHAIN_FILE_x86_64-apple-darwin = None
  CMAKE_TOOLCHAIN_FILE_x86_64_apple_darwin = None
  TARGET_CMAKE_TOOLCHAIN_FILE = None
  CMAKE_TOOLCHAIN_FILE = None
  CMAKE_GENERATOR_x86_64-apple-darwin = None
  CMAKE_GENERATOR_x86_64_apple_darwin = None
  TARGET_CMAKE_GENERATOR = None
  CMAKE_GENERATOR = None
  cargo:warning=Compiler family detection failed due to error: ToolExecError: command did not execute successfully (status code exit status: 1): "/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang" "-E" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/17340652778166554238detect_compiler_family.c"
  cargo:warning=osxcross: error: cannot find libc++ headers
  cargo:warning=osxcross: error: while detecting target
  cargo:warning=Compiler family detection failed due to error: ToolExecError: command did not execute successfully (status code exit status: 1): "/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang" "-E" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/17287014108017272515detect_compiler_family.c"
  cargo:warning=osxcross: error: cannot find libc++ headers
  cargo:warning=osxcross: error: while detecting target
  cargo:warning=Compiler family detection failed due to error: ToolExecError: command did not execute successfully (status code exit status: 1): "/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang" "-E" "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/900956184758601671detect_compiler_family.c"
  cargo:warning=osxcross: error: cannot find libc++ headers
  cargo:warning=osxcross: error: while detecting target
  CMAKE_PREFIX_PATH_x86_64-apple-darwin = None
  CMAKE_PREFIX_PATH_x86_64_apple_darwin = None
  TARGET_CMAKE_PREFIX_PATH = None
  CMAKE_PREFIX_PATH = None
  CMAKE_x86_64-apple-darwin = None
  CMAKE_x86_64_apple_darwin = None
  TARGET_CMAKE = None
  CMAKE = None
  running: cd "/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/build" && CMAKE_PREFIX_PATH="" LC_ALL="C" "cmake" "/home/developer/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/fltk-sys-1.5.9/cfltk" "-DFLTK_USE_SYSTEM_LIBPNG=OFF" "-DFLTK_USE_SYSTEM_LIBJPEG=OFF" "-DFLTK_USE_SYSTEM_ZLIB=OFF" "-DCFLTK_LINK_IMAGES=ON" "-DOpenGL_GL_PREFERENCE=GLVND" "-DFLTK_BUILD_GL=OFF" "-DCFLTK_USE_OPENGL=OFF" "-DCMAKE_OSX_DEPLOYMENT_TARGET=10.15" "-DCMAKE_OSX_SYSROOT=macosx" "-DCMAKE_OSX_ARCHITECTURES=x86_64" "-DCMAKE_EXPORT_COMPILE_COMMANDS=ON" "-DCFLTK_CARGO_BUILD=ON" "-DFLTK_BUILD_EXAMPLES=OFF" "-DFLTK_BUILD_TEST=OFF" "-DFLTK_BUILD_FLUID=OFF" "-DFLTK_BUILD_FLTK_OPTIONS=OFF" "-DFLTK_OPTION_LARGE_FILE=ON" "-DFLTK_BUILD_HTML_DOCS=OFF" "-DFLTK_BUILD_PDF_DOCS=OFF" "-DCMAKE_SYSTEM_NAME=Darwin" "-DCMAKE_SYSTEM_PROCESSOR=x86_64" "-DCMAKE_INSTALL_PREFIX=/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out" "-DCMAKE_C_FLAGS= -ffunction-sections -fdata-sections -fPIC -m64 --target=x86_64-apple-macosx -mmacosx-version-min=10.15" "-DCMAKE_C_COMPILER=/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang" "-DCMAKE_CXX_FLAGS= -ffunction-sections -fdata-sections -fPIC -m64 --target=x86_64-apple-macosx -mmacosx-version-min=10.15" "-DCMAKE_CXX_COMPILER=/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang" "-DCMAKE_ASM_FLAGS= -ffunction-sections -fdata-sections -fPIC -m64 --target=x86_64-apple-macosx -mmacosx-version-min=10.15" "-DCMAKE_ASM_COMPILER=/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang" "-DCMAKE_BUILD_TYPE=Debug"
  -- The C compiler identification is unknown
  -- The CXX compiler identification is unknown
  -- Detecting C compiler ABI info
  -- Detecting C compiler ABI info - failed
  -- Check for working C compiler: /home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang
  -- Check for working C compiler: /home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang - broken
  -- Configuring incomplete, errors occurred!

  --- stderr
  CMake Error at /usr/share/cmake-3.28/Modules/CMakeTestCCompiler.cmake:67 (message):
    The C compiler

      "/home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang"

    is not able to compile a simple test program.

    It fails with the following output:

      Change Dir: '/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/build/CMakeFiles/CMakeScratch/TryCompile-xsFRw1'
      
      Run Build Command(s): /usr/bin/cmake -E env VERBOSE=1 /usr/bin/gmake -f Makefile cmTC_ea83b/fast
      /usr/bin/gmake  -f CMakeFiles/cmTC_ea83b.dir/build.make CMakeFiles/cmTC_ea83b.dir/build
      gmake[1]: Entering directory '/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/build/CMakeFiles/CMakeScratch/TryCompile-xsFRw1'
      Building C object CMakeFiles/cmTC_ea83b.dir/testCCompiler.c.o
      /home/developer/osxcross/target/bin/x86_64-apple-darwin19-clang   -ffunction-sections -fdata-sections -fPIC -m64 --target=x86_64-apple-macosx -mmacosx-version-min=10.15  -arch x86_64 -o CMakeFiles/cmTC_ea83b.dir/testCCompiler.c.o -c /home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/build/CMakeFiles/CMakeScratch/TryCompile-xsFRw1/testCCompiler.c
      osxcross: error: cannot find libc++ headers
      osxcross: error: while detecting target
      gmake[1]: *** [CMakeFiles/cmTC_ea83b.dir/build.make:78: CMakeFiles/cmTC_ea83b.dir/testCCompiler.c.o] Error 1
      gmake[1]: Leaving directory '/home/developer/rust/fltkmenu/target/x86_64-apple-darwin/debug/build/fltk-sys-2ac5100b81d2f71e/out/build/CMakeFiles/CMakeScratch/TryCompile-xsFRw1'
      gmake: *** [Makefile:127: cmTC_ea83b/fast] Error 2
      
      

    

    CMake will not be able to correctly generate this project.
  Call Stack (most recent call first):
    CMakeLists.txt:4 (project)



  thread 'main' panicked at /home/developer/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/cmake-0.1.54/src/lib.rs:1119:5:

  command did not execute successfully, got: exit status: 1

  build script failed, must exit now
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...

[MoAlyousef]

There seems to be an issue with your packaged SDK.

[ds2k5]

@MoAlyousef

Ok thanks .... did not know how to fix