Results of CMake confchecks not propagated back to main CMakeLists.txt

[MHBalsmeier]

Describe the bug
The results of the wrf_conf_check calls are variables that are either 0 or 1 indicating success or no success. They are, however, always seen as 0 by the main CMakeLists.txt.

To Reproduce

1. ./cleanCMake.sh -a
2. Add the print debug statements given in the Screenshot below.
3. ./configure_new, observe the console output and the resulting compile flags.

Expected behavior
The results of the confchecks should be visible in the main CMakeLists.txt

Screenshots

Resulting console output:

Fortran_2003_GAMMA=
-- Performing Check Fortran_2003_IEEE
-- Performing Check Fortran_2003_IEEE - Success
-- Performing Check Fortran_2003_ISO_C
-- Performing Check Fortran_2003_ISO_C - Success
-- Performing Check Fortran_2003_FLUSH
-- Performing Check Fortran_2003_FLUSH - Success
-- Performing Check Fortran_2003_GAMMA
-- Performing Check Fortran_2003_GAMMA - Success
-- Performing Check FSEEKO64
-- Performing Check FSEEKO64 - Success
Fortran_2003_GAMMA=0

So while the confcheck indicates success, the resulting variable arrives as 0 in the main CMakeLists.txt, so intrinsic gamma function support is disabled, resulting for example in the GF cumulus physics not working.

[MHBalsmeier]

I have a fix for that in https://github.com/MHBalsmeier/WRF/tree/confcheck_fix that works for me.
I could open a pull request if the modifications make sense to you guys.

[islas]

@MHBalsmeier Please go forward with a pull request using your fix.

I believe the issue stems from #2090 also changing the call from a macro() to a function() which pushed the variables down one scope. While we could revert this and reinstate these calls as macros, I think the approach to keep them as functions and manually control the scope to the parent, as you did, is preferable.