Intel-only flags cause errors for GCC

[AlexanderRichert-NOAA]

Description

Building with GCC fails on radmon component because radmon.fd/CMakeLists.txt uses Intel-specific flags. The set(CMAKE_Fortran_FLAGS... line should be in an if block (if (CMAKE_Fortran_COMPILER_ID MATCHES "^Intel$") or something to that effect, possibly accompanied by equivalent flags for other compilers.

Steps to Reproduce/Output

CC=gcc FC=gfortran cmake -B build # I'm using GCC 13.2.1
CC=gcc FC=gfortran cmake --build build

Output:

...
[ 59%] Building Fortran object radmon.fd/shared/CMakeFiles/radmonlib.dir/kinds_radmon.F90.o
gfortran: error: unrecognized command-line option ‘-fp-model’
gfortran: error: unrecognized command-line option ‘-assume’
gfortran: error: unrecognized command-line option ‘-convert’; did you mean ‘--convert=’?
gmake[2]: *** [radmon.fd/shared/CMakeFiles/radmonlib.dir/build.make:75: radmon.fd/shared/CMakeFiles/radmonlib.dir/kinds_radmon.F90.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:1423: radmon.fd/shared/CMakeFiles/radmonlib.dir/all] Error 2
gmake: *** [Makefile:136: all] Error 2