cmake COMPILER_RT_HAS_LIBC examples

Lewuathe/mlir-hello thirdparty/llvm-project/compiler-rt/cmake/config-ix.cmake :20 

check_library_exists(c fopen "" COMPILER_RT_HAS_LIBC)

trailofbits/polytracker polytracker/src/compiler-rt/cmake/config-ix.cmake :16 

check_library_exists(c fopen "" COMPILER_RT_HAS_LIBC)

CTSRD-CHERI/cheribsd contrib/subrepo-cheri-compiler-rt/cmake/config-ix.cmake :20 

check_library_exists(c fopen "" COMPILER_RT_HAS_LIBC)