sdl12-compat: macos: Replace deprecated NSAlternateKeyMask.

From d7b138c82a63d4b10ca25d0ee768636482b8ecc6 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sat, 11 Dec 2021 13:36:01 -0500
Subject: [PATCH] macos: Replace deprecated NSAlternateKeyMask.

---
 src/SDLmain/macosx/SDLMain.m | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/SDLmain/macosx/SDLMain.m b/src/SDLmain/macosx/SDLMain.m
index 2b46632..673f89d 100644
--- a/src/SDLmain/macosx/SDLMain.m
+++ b/src/SDLmain/macosx/SDLMain.m
@@ -17,6 +17,9 @@ @interface NSApplication(SDL_Missing_Methods)
 - (void)setAppleMenu:(NSMenu *)menu;
 @end
 
+/* NSEventModifierFlagOption replaced NSAlternateKeyMask in 10.12, but it's the same value. */
+#define EventModifierFlagOption (1 << 19)
+
 /* Use this flag to determine whether we use SDLMain.nib or not */
 #define		SDL_USE_NIB_FILE	0
 
@@ -139,7 +142,7 @@ static void setApplicationMenu(void)
     [appleMenu addItemWithTitle:title action:@selector(hide:) keyEquivalent:@"h"];
 
     menuItem = (NSMenuItem *)[appleMenu addItemWithTitle:@"Hide Others" action:@selector(hideOtherApplications:) keyEquivalent:@"h"];
-    [menuItem setKeyEquivalentModifierMask:(NSAlternateKeyMask|NSCommandKeyMask)];
+    [menuItem setKeyEquivalentModifierMask:(EventModifierFlagOption|NSCommandKeyMask)];
 
     [appleMenu addItemWithTitle:@"Show All" action:@selector(unhideAllApplications:) keyEquivalent:@""];