+/* Zero means that faster, ...NonNil variants of objc_msgSend...
+ calls will be used in ObjC; passing nil receivers to such calls
+ will most likely result in crashes. */
+extern int flag_nil_receivers;
+
+/* Nonzero means that we will allow new ObjC exception syntax (@throw,
+ @try, etc.) in source code. */
+extern int flag_objc_exceptions;
+
+/* Nonzero means that code generation will be altered to support
+ "zero-link" execution. This currently affects ObjC only, but may
+ affect other languages in the future. */
+extern int flag_zero_link;
+
+/* Nonzero means emit an '__OBJC, __image_info' for the current translation
+ unit. It will inform the ObjC runtime that class definition(s) herein
+ contained are to replace one(s) previously loaded. */
+extern int flag_replace_objc_classes;
+