cmake COMPILER_RT_HAS_LIBCXX examples

Lewuathe/mlir-hello thirdparty/llvm-project/compiler-rt/cmake/config-ix.cmake :200 

check_library_exists(c++ __cxa_throw "" COMPILER_RT_HAS_LIBCXX)

trailofbits/polytracker polytracker/src/compiler-rt/cmake/config-ix.cmake :155 

check_library_exists(c++ __cxa_throw "" COMPILER_RT_HAS_LIBCXX)

CTSRD-CHERI/cheribsd contrib/subrepo-cheri-compiler-rt/cmake/config-ix.cmake :192 

check_library_exists(c++ __cxa_throw "" COMPILER_RT_HAS_LIBCXX)