fix MacOS compilation

Makefile

@@ -136,7 +136,9 @@ else ifeq ($(platform), osx)
    endif
    OSXVER = `sw_vers -productVersion | cut -d. -f 2`
    OSX_LT_MAVERICKS = `(( $(OSXVER) <= 9)) && echo "YES"`
-   fpic += -mmacosx-version-min=10.1
+   fpic += -mmacosx-version-min=10.7
+   CXXFLAGS += -stdlib=libc++
+   LDFLAGS += -stdlib=libc++
 
 # iOS
 else ifneq (,$(findstring ios,$(platform)))