This is a CMake Environment Variable. Its initial value is taken from the calling process environment.
Default compilation flags to be used when compiling
Fortran files. Will only
be used by CMake on the first configuration to determine
compilation flags, after which the value for
FFLAGS is stored in the cache
CMAKE_Fortran_FLAGS. For any configuration
run (including the first), the environment variable will be ignored if
CMAKE_Fortran_FLAGS variable is defined.