Correct way to set compiler flags

[climbfuji]

Currently, the cmake build system uses CMAKE_Fortran_FLAGS as default compiler options for all CAPS and SCHEMES. These options are added to the compiler options for individual files, because of the definition

set_target_properties(ccppphys PROPERTIES VERSION ${PROJECT_VERSION}
                                     SOVERSION ${PROJECT_VERSION_MAJOR}
                                     COMPILE_FLAGS "${CMAKE_Fortran_FLAGS}"
                                     LINK_FLAGS "${CMAKE_Fortran_FLAGS}")

Because of this, forcing certain compiler options (or removing them) for individual files does not work.

Example: in order to compile gfdl_fv_sat_adj.F90 with default real kind 4 with the GNU compilers, it is necessary to remove the "-fdefault-real-8" compiler option, which the current system doesn't allow. For Intel, this problem is overcome by adding "-real-size 32" to the compiler options for this file. When the compiler options are combined, "-real-size 32" ends up after "-real-size 64" and as such overwrites "-real-size 64". For the PGI compiler, this has not been tested yet.

The correct way to do this would be to specify default compiler options for all CAPS and SCHEMES before adjustments are made for individual files, and remove COMPILE_FLAGS and LINK_FLAGS fro the above code snippet.

[climbfuji]

In general addressed by https://github.com/NCAR/NEMSfv3gfs/pull/113.