Update TestVBool Makefile to allow building test program with gcc

- do not pass (incompatible option) -stdlib=libstdc++ option if using GCC as test compiler

llvm-svn: 175522

lldb/test/functionalities/data-formatter/data-formatter-stl/libstdcpp/vbool/Makefile

@@ -4,5 +4,8 @@ CXX_SOURCES := main.cpp
 
 include $(LEVEL)/Makefile.rules
 
-CXXFLAGS += -stdlib=libstdc++ -O0
+CXXFLAGS += -O0
+ifeq (,$(findstring gcc,$(CC)))
+CXXFLAGS += -stdlib=libstdc++
 LDFLAGS += -stdlib=libstdc++
+endif