Index: cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- cmake/modules/HandleLLVMOptions.cmake
+++ cmake/modules/HandleLLVMOptions.cmake
@@ -249,6 +249,10 @@
   if (LLVM_ENABLE_CXX11)
     check_cxx_compiler_flag("-std=c++11" CXX_SUPPORTS_CXX11)
     append_if(CXX_SUPPORTS_CXX11 "-std=c++11" CMAKE_CXX_FLAGS)
+    if (APPLE)
+      check_cxx_compiler_flag("-stdlib=libc++" CXX_SUPPORTS_STDLIB)
+      append_if(CXX_SUPPORTS_STDLIB "-stdlib=libc++" CMAKE_CXX_FLAGS)
+    endif ()
   endif (LLVM_ENABLE_CXX11)
 endif( MSVC )