macOS Sierra (10.12): Disallow Automatic Window Tabbing

Automatic Window Tabbing in macOS Sierra causes a menu item called "Show
Tab Bar" to appear under the Window menu in the menu bar. Selecting this
option causes a double-title bar effect as there is no option in OpenRCT2
to make new tabbed "documents". This double-title bar can be untoggled
by selecting "Hide Tab Bar".

I don't think OpenRCT2 is going to become a tabbed document-oriented
themepark simulator anytime soon. Thanks, but no thanks Sierra.

References:
* https://codereview.chromium.org/2325313002/
* https://hg.mozilla.org/releases/mozilla-aurora/rev/385b9ea08ff7

* Use better Obj-C styling for macos_disallow_automatic_window_tabbing()

src/openrct2/platform/macos.m

@@ -24,6 +24,15 @@
 #include "../localisation/language.h"
 #include "../config/Config.h"
 
+void macos_disallow_automatic_window_tabbing()
+{
+	@autoreleasepool {
+		if ([NSWindow respondsToSelector:@selector(setAllowsAutomaticWindowTabbing:)]) {
+			[NSWindow setAllowsAutomaticWindowTabbing:NO];
+		}
+	}
+}
+
 bool platform_check_steam_overlay_attached() {
 	STUB();
 	return false;

src/openrct2/platform/platform.h

@@ -235,4 +235,8 @@ void core_init();
 	void platform_posix_sub_resolve_openrct_data_path(utf8 *out, size_t size);
 #endif
 
+#ifdef __MACOSX__
+	void macos_disallow_automatic_window_tabbing();
+#endif
+
 #endif

src/openrct2/platform/shared.c

@@ -617,6 +617,9 @@ static void platform_create_window()
 	SDL_SetWindowGrab(gWindow, gConfigGeneral.trap_cursor ? SDL_TRUE : SDL_FALSE);
 	SDL_SetWindowMinimumSize(gWindow, 720, 480);
 	platform_init_window_icon();
+#ifdef __MACOSX__
+	macos_disallow_automatic_window_tabbing();
+#endif
 
 	// Initialise the surface, palette and draw buffer
 	platform_resize(width, height);