[CMake] Remove -stdlib= which is unused when passing -nostdinc++

This avoids the warnings when building with LLVM_ENABLE_LIBCXX
which automatically adds -stdlib=libc++ to CMAKE_CXX_FLAGS.

Differential Revision: https://reviews.llvm.org/D42238

llvm-svn: 323969

compiler-rt/lib/fuzzer/CMakeLists.txt

@@ -35,6 +35,8 @@ set(LIBFUZZER_CFLAGS ${SANITIZER_COMMON_CFLAGS})
 
 if("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux" AND COMPILER_RT_LIBCXX_PATH)
   list(APPEND LIBFUZZER_CFLAGS -nostdinc++ -D_LIBCPP_ABI_VERSION=Fuzzer)
+  # Remove -stdlib= which is unused when passing -nostdinc++.
+  string(REGEX REPLACE "-stdlib=[a-zA-Z+]*" "" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
 endif()
 
 append_list_if(COMPILER_RT_HAS_OMIT_FRAME_POINTER_FLAG -fno-omit-frame-pointer LIBFUZZER_CFLAGS)

compiler-rt/lib/msan/tests/CMakeLists.txt

@@ -37,6 +37,9 @@ set(MSAN_UNITTEST_COMMON_CFLAGS
   -Werror=sign-compare
   -Wno-gnu-zero-variadic-macro-arguments
 )
+# Remove -stdlib= which is unused when passing -nostdinc++.
+string(REGEX REPLACE "-stdlib=[a-zA-Z+]*" "" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
+
 set(MSAN_UNITTEST_INSTRUMENTED_CFLAGS
   ${MSAN_UNITTEST_COMMON_CFLAGS}
   -fsanitize=memory