Define CFLAGS for conforming macosx environment

gitlab/functions.sh

@@ -206,6 +206,8 @@ if [ "${ARCH}" == "linux" ]; then
   else
     CFLAGS="${CFLAGS} -D_GLIBCXX_USE_CXX11_ABI=0"
   fi
+else
+  CFLAGS=""
 fi
 CXXFLAGS=${CFLAGS}