Index: compiler-rt/trunk/lib/fuzzer/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/lib/fuzzer/CMakeLists.txt
+++ compiler-rt/trunk/lib/fuzzer/CMakeLists.txt
@@ -35,6 +35,8 @@
 
 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)
Index: compiler-rt/trunk/lib/msan/tests/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/lib/msan/tests/CMakeLists.txt
+++ compiler-rt/trunk/lib/msan/tests/CMakeLists.txt
@@ -37,6 +37,9 @@
   -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