Fixed bug 3786 - building against a Mac OS X SDK < 10.11 fails since the vulkan merge

Ozkan Sezer

Since the Vulkan merge, building against a Mac OS X SDM older than
10.11 fails in SDL_cocoametalview.m because Metal.framework is not
present. There is no conditional compiling in SDL_cocoametalview.m
either, so --disable-video-vulkan doesn't help with anything. (The
configury doesn't check darwin for x86_64 either, but it's another
story.)

I cross-build against 10.8 SDK on linux using clang-3.4.2 and this
is a problem for me.  Will this be fixed?

src/video/cocoa/SDL_cocoametalview.h

@@ -32,6 +32,8 @@
 #import "../SDL_sysvideo.h"
 #import "SDL_cocoawindow.h"
 
+#if SDL_VIDEO_VULKAN && SDL_VIDEO_DRIVER_COCOA
+
 #import <Cocoa/Cocoa.h>
 #import <Metal/Metal.h>
 #import <QuartzCore/CAMetalLayer.h>
@@ -55,6 +57,8 @@ SDL_cocoametalview* Cocoa_Mtl_AddMetalView(SDL_Window* window);
 
 void Cocoa_Mtl_GetDrawableSize(SDL_Window * window, int * w, int * h);
 
+#endif /* SDL_VIDEO_VULKAN && SDL_VIDEO_DRIVER_COCOA */
+
 #endif /* SDL_cocoametalview_h_ */
 
 /* vi: set ts=4 sw=4 expandtab: */

src/video/cocoa/SDL_cocoametalview.m

@@ -28,6 +28,8 @@
 
 #import "SDL_cocoametalview.h"
 
+#if SDL_VIDEO_VULKAN && SDL_VIDEO_DRIVER_COCOA
+
 #include "SDL_assert.h"
 #include "SDL_loadso.h"
 #include <dlfcn.h>
@@ -116,5 +118,6 @@ Cocoa_Mtl_GetDrawableSize(SDL_Window * window, int * w, int * h)
     }
 }
 
-/* vi: set ts=4 sw=4 expandtab: */
+#endif /* SDL_VIDEO_VULKAN && SDL_VIDEO_DRIVER_COCOA */
 
+/* vi: set ts=4 sw=4 expandtab: */