Continue to support Lion. Reverts
https://github.com/wesnoth/wesnoth/commit/01d599886629af15ddc15a696f61fdf3ceb64323
--- src/macosx/SDLMain.mm.orig	2022-01-16 12:10:36.000000000 -0600
+++ src/macosx/SDLMain.mm	2022-01-21 08:56:16.000000000 -0600
@@ -141,7 +141,11 @@
 
 	[WesnothSDLApplication sharedApplication];
 
+	if ([[NSBundle mainBundle] respondsToSelector:@selector(loadNibNamed:owner:topLevelObjects:)]) {
 	[[NSBundle mainBundle] loadNibNamed:@"SDLMain" owner:NSApp topLevelObjects:nil];
+	} else {
+	[NSBundle loadNibNamed:@"SDLMain" owner:NSApp];
+	}
 
 	[NSApp run];
 	return 0;