diff --git a/build/osx/wx.xcconfig b/build/osx/wx.xcconfig
index 42339d528b..32562b63dd 100644
--- a/build/osx/wx.xcconfig
+++ b/build/osx/wx.xcconfig
@@ -5,7 +5,7 @@
 WXPLATFORM = __WXOSX_$(WXTOOLKITUPPER)__
 PRODUCT_NAME = wx_osx_$(WXTOOLKIT)
 
-OTHER_CFLAGS = -Wall -Wundef -fno-strict-aliasing -fno-common -fvisibility=hidden 
+OTHER_CFLAGS = -Wall -Wno-undef -fno-strict-aliasing -fno-common -fvisibility=hidden 
 OTHER_CPLUSPLUSFLAGS = $(OTHER_CFLAGS) -fvisibility-inlines-hidden
 
 GCC_PREFIX_HEADER = $(WXROOT)/include/wx/wxprec.h
@@ -17,3 +17,5 @@ WX_PREPROCESSOR_DEFINITIONS = WXBUILDING $(WXPLATFORM) __WX__ _FILE_OFFSET_BITS=
 GCC_PREPROCESSOR_DEFINITIONS = $(WX_PREPROCESSOR_DEFINITIONS)
 GCC_PFE_FILE_C_DIALECTS = c++ objective-c++
 GCC_C_LANGUAGE_STANDARD = gnu99
+CLANG_CXX_LANGUAGE_STANDARD = gnu++11
+CLANG_CXX_LIBRARY = libc++