Update Build.xml

Author: HomuHomu833

project/Build.xml

@@ -14,7 +14,7 @@
 
 	<set name="HXCPP_ANDROID_PLATFORM" value="24" if="android" />
 	<set name="PLATFORM_NUMBER" value="24" if="android" />
-	<setenv name="MACOSX_DEPLOYMENT_TARGET" value="10.13" if="mac" />
+	<setenv name="MACOSX_DEPLOYMENT_TARGET" value="12" if="mac" />
 
 	<set name="LIME_CAIRO" value="1" />
 	<set name="LIME_CURL" value="1" />