Fix MingW build test

[petercolberg]

Fix MingW build test

[aviks]

@petercolberg I've added the [WIP] tag to the title to indicate that this is experimental. Please take it out once this PR is ready.

[tkelman]

The problem is that cd /c/projects/utf8proc is failing in msys, not the choice of generator. mingw make is a crippled version that is enough to build utf8proc but not much else.

[petercolberg]

If the line that creates /etc/fstab is removed, then cd /c/projects/utf8proc succeeds.

The build freezes as soon as cmake … -G'MSYS Makefiles' is executed.

[petercolberg]

I could finally trigger the following graphical error dialog in the interactive session:

cc1.exe: The program can't start because libgmp-10.dll is missing from your computer.
Try reinstalling the program to fix this problem.

This is why cmake hangs when using the MSYS Makefiles generator.

[tkelman]

That sounds like a broken toolchain installation, cc @FeodorFitsner. So changing the generator must be either changing which mingw compiler is getting run, or modifying the path so it's able to find libgmp.

[petercolberg]

It’s already fixed. Please review after the Travis build succeeds.

[stevengj]

Looks great, thanks for following up on this!