[macOS] Fix some deprecation warnings.

platform/macos/display_server_macos.mm

@@ -2686,7 +2686,7 @@ Ref<Image> DisplayServerMacOS::clipboard_get_image() const {
 		return image;
 	}
 	NSBitmapImageRep *bitmap = [NSBitmapImageRep imageRepWithData:data];
-	NSData *pngData = [bitmap representationUsingType:NSPNGFileType properties:@{}];
+	NSData *pngData = [bitmap representationUsingType:NSBitmapImageFileTypePNG properties:@{}];
 	image.instantiate();
 	PNGDriverCommon::png_to_image((const uint8_t *)pngData.bytes, pngData.length, false, image);
 	return image;

platform/macos/godot_application.mm

@@ -100,7 +100,7 @@
 }
 
 - (void)sendEvent:(NSEvent *)event {
-	if ([event type] == NSSystemDefined && [event subtype] == 8) {
+	if ([event type] == NSEventTypeSystemDefined && [event subtype] == 8) {
 		int keyCode = (([event data1] & 0xFFFF0000) >> 16);
 		int keyFlags = ([event data1] & 0x0000FFFF);
 		int keyState = (((keyFlags & 0xFF00) >> 8)) == 0xA;

platform/macos/os_macos.mm

@@ -601,7 +601,9 @@ Error OS_MacOS::create_process(const String &p_path, const List<String> &p_argum
 		for (const String &arg : p_arguments) {
 			[arguments addObject:[NSString stringWithUTF8String:arg.utf8().get_data()]];
 		}
+#if defined(__x86_64__)
 		if (@available(macOS 10.15, *)) {
+#endif
 			NSWorkspaceOpenConfiguration *configuration = [[NSWorkspaceOpenConfiguration alloc] init];
 			[configuration setArguments:arguments];
 			[configuration setCreatesNewApplicationInstance:YES];
@@ -630,6 +632,7 @@ Error OS_MacOS::create_process(const String &p_path, const List<String> &p_argum
 			}
 
 			return err;
+#if defined(__x86_64__)
 		} else {
 			Error err = ERR_TIMEOUT;
 			NSError *error = nullptr;
@@ -645,6 +648,7 @@ Error OS_MacOS::create_process(const String &p_path, const List<String> &p_argum
 			}
 			return err;
 		}
+#endif
 	} else {
 		return OS_Unix::create_process(p_path, p_arguments, r_child_id, p_open_console);
 	}