[cmake] Quote args when generating /libpath option specifying runtime dir for link/lld-link

[ormris]

Summary

When the runtime dir path includes whitespace (ex. when it's installed under "Program Files" on Windows), the lack of quotes causes the linker to interpret the path as one or more arguments. None of these path fragments exist, so the link fails.

[smeenai]

LGTM

[ormris]

Thanks!

llvm/cmake/modules/HandleLLVMOptions.cmake

execute_process(
     ERROR_STRIP_TRAILING_WHITESPACE
     RESULT_VARIABLE clang_cl_exit_code)
   if (NOT "${clang_cl_exit_code}" STREQUAL "0")
     message(FATAL_ERROR
       "Unable to invoke clang-cl to find resource dir: ${clang_cl_stderr}")
   endif()
   file(TO_CMAKE_PATH "${clang_compiler_rt_file}" clang_compiler_rt_file)
   get_filename_component(clang_runtime_dir "${clang_compiler_rt_file}" DIRECTORY)
-  append("/libpath:${clang_runtime_dir}"
+  append("/libpath:\"${clang_runtime_dir}\""
     CMAKE_EXE_LINKER_FLAGS
     CMAKE_MODULE_LINKER_FLAGS
     CMAKE_SHARED_LINKER_FLAGS)
 endif()
 
 if(LLVM_PROFDATA_FILE AND EXISTS ${LLVM_PROFDATA_FILE})
   if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" )
     append("-fprofile-instr-use=\"${LLVM_PROFDATA_FILE}\""