Merge pull request #176 from Code-Hex/fix/175

fixed to be compilable on macOS 12

Author: Code-Hex

virtualization_view.h

@@ -6,6 +6,7 @@
 
 #pragma once
 
+#import "virtualization_helper.h"
 #import <Availability.h>
 #import <Cocoa/Cocoa.h>
 #import <Virtualization/Virtualization.h>

virtualization_view.m

@@ -453,7 +453,8 @@ - (void)setupGraphicWindow
 // distortion within the window.
 - (NSSize)getVirtualMachineSizeInPixels
 {
-    __block NSSize sizeInPixels;
+    __block NSSize sizeInPixels = NSZeroSize;
+#ifdef INCLUDE_TARGET_OSX_14
     if (@available(macOS 14.0, *)) {
         dispatch_sync(_queue, ^{
             if (_virtualMachine.graphicsDevices.count > 0) {
@@ -465,6 +466,7 @@ - (NSSize)getVirtualMachineSizeInPixels
             }
         });
     }
+#endif
     return sizeInPixels;
 }