Revert "CMake: Pass `OpenMP` compiler and linker flags through CMake … #5975

Job	Run time
cross_build (riscv64, riscv64-linux-gnu, TARGET=RISCV64_GENERIC)	2m 40s
cross_build (mips64el, mips64el-linux-gnuabi64, DYNAMIC_ARCH=1 TARGET=GENERIC)	3m 40s
cross_build (alpha, alpha-linux-gnu, TARGET=EV4)	3m 1s
neoverse_build	7m 45s
build (ubuntu-latest, gfortran, cmake)	46m 41s
cross_build (mipsel, mipsel-linux-gnu, TARGET=MIPS1004K)	3m 32s
build (macos-latest, gfortran, cmake)	23m 52s
build (ubuntu-latest, flang, make)	5m 1s
build (ubuntu-latest, gfortran, make)	22m 50s
build (ubuntu-latest, flang, cmake)	10m 14s
msys2 (CLANG64, int32, Release)	15m 9s
msys2 (UCRT64, int32, Release)	14m 28s
msys2 (MINGW32, int32, Release)	17m 10s
build (macos-latest, gfortran, make)	7m 0s
msys2 (UCRT64, int64, Release)	13m 35s
msys2 (CLANG64, int64, Release)	17m 0s
msys2 (UCRT64, int32, None, mingw-w64-ucrt-x86_64, fc)	11m 35s
	3h 45m 13s

Provide feedback