cmake COMPILER_RT_HAS_LIBRT examples

Lewuathe/mlir-hello thirdparty/llvm-project/compiler-rt/cmake/config-ix.cmake :191 

check_library_exists(rt shm_open "" COMPILER_RT_HAS_LIBRT)

trailofbits/polytracker polytracker/src/compiler-rt/cmake/config-ix.cmake :131 

check_library_exists(rt shm_open "" COMPILER_RT_HAS_LIBRT)

CTSRD-CHERI/cheribsd contrib/subrepo-cheri-compiler-rt/cmake/config-ix.cmake :168 

check_library_exists(rt shm_open "" COMPILER_RT_HAS_LIBRT)