Remove -Werror when using check_cxx_compiler_flag because it was causing compiler-rt breakages.

llvm-svn: 243784
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 16bd6cbdf0fddbe5bee1a4ef17b0c1ac8c305d72
diff --git a/cmake/Modules/HandleLibcxxFlags.cmake b/cmake/Modules/HandleLibcxxFlags.cmake
index 2a450da..223b7b7 100644
--- a/cmake/Modules/HandleLibcxxFlags.cmake
+++ b/cmake/Modules/HandleLibcxxFlags.cmake
@@ -96,7 +96,7 @@
 macro(add_compile_flags_if_supported)
   foreach(flag ${ARGN})
       mangle_name("${flag}" flagname)
-      check_cxx_compiler_flag("-Werror ${flag}" "LIBCXX_SUPPORTS_${flagname}_FLAG")
+      check_cxx_compiler_flag("${flag}" "LIBCXX_SUPPORTS_${flagname}_FLAG")
       add_compile_flags_if(LIBCXX_SUPPORTS_${flagname}_FLAG ${flag})
   endforeach()
 endmacro()