Fix iOS build

ui/drivers/cocoa/cocoa_common.h

@@ -37,13 +37,15 @@ typedef enum apple_view_type {
 } apple_view_type_t;
 
 @protocol PlatformDelegate
+#ifdef HAVE_METAL
 @optional
 - (void)viewDidUpdateFrame:(NSRect)rect;
+#endif
 @end
 
 @protocol ApplePlatform
 
-@property (readwrite) id<PlatformDelegate> delegate;
+@property (readwrite,retain) id<PlatformDelegate> delegate;
 
 /*!
  @brief viewHandle returns an appropriate handle for the current view type

ui/drivers/ui_cocoatouch.m

@@ -41,7 +41,7 @@
 #endif
 
 static char msg_old[PATH_MAX_LENGTH];
-static id<ApplePlatform> apple_platform;
+id<ApplePlatform> apple_platform;
 static CFRunLoopObserverRef iterate_observer;
 
 /* forward declaration */