Fixed warning from __objc_get_forward_imp not returning a value

From-SVN: r54707

libobjc/sendmsg.c

@@ -83,13 +83,17 @@ __inline__
 IMP 
 __objc_get_forward_imp (SEL sel) 
 { 
+  /* If a custom forwarding hook was registered, try getting a forwarding
+   * function from it.  */
   if (__objc_msg_forward) 
     { 
       IMP result; 
-      if ((result = __objc_msg_forward (sel)))
+      if ((result = __objc_msg_forward (sel)) != NULL) 
         return result; 
     } 
-  else
+
+  /* In all other cases, use the default forwarding functions built using
+   * __builtin_apply and friends.  */
   { 
     const char *t = sel->sel_types;