sdl12-compat: The APPLICATION key should actually map to MENU.

SDL Commits
1 
From 0ee69695fd453993de86627b8a9c29f0976390e0 Mon Sep 17 00:00:00 2001
From: David Gow <[EMAIL REDACTED]>
Date: Thu, 10 Jun 2021 17:27:17 +0800
Subject: [PATCH] The APPLICATION key should actually map to MENU.

This is described in the SDL 2.0 docs as being either a compose key
(notably an actual, hardware compose key like the type seen on old Sun
keyboards) or the windows contextual menu. On my Linux/X11 machine with
a Microsoft USB keyboard, this is the scancode the contextual menu uses.
(What, if anything, ever produces the MENU scancode is a mystery for
another day, I guess...)
---
 src/SDL12_compat.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/SDL12_compat.c b/src/SDL12_compat.c
index d795ae1..6ff5000 100644
--- a/src/SDL12_compat.c
+++ b/src/SDL12_compat.c
@@ -2396,8 +2396,8 @@ Scancode20toKeysym12(const SDL_Scancode scancode20)
     CASESCANCODE20TOKEY12(KP_0,KP0);
 
     CASESCANCODE20TOKEY12(NONUSBACKSLASH,BACKSLASH);
-    /* The description of this could be MENU, or COMPOSE, or neither. */
-    CASESCANCODE20TOKEY12(APPLICATION,COMPOSE);
+    /* In theory, this could be MENU, or COMPOSE, or neither, but on my machine, it's MENU. */
+    CASESCANCODE20TOKEY12(APPLICATION,MENU);
     CASESCANCODE20TOKEY12(POWER,POWER);
     CASESCANCODE20TOKEY12(F13,F13);
     CASESCANCODE20TOKEY12(F14,F14);