Feature flags possible to add in project.json. See #991

resources/testproject/hello_world.c3

@@ -11,5 +11,7 @@ fn int main()
     printf("Hello World!\n");
     bar::test();
     printf("Hello double: %d\n", test_doubler(11));
+	if ($feature(ABCD)) io::printn("ABCD");
+
     return 0;
 }

resources/testproject/project.json

@@ -14,6 +14,8 @@
   // libraries to use
   "dependencies": [],
 
+  "features": ["ABCD"],
+
   // c compiler
   "cc": "cc",
   // c sources