sdl12-compat: The Command key should be exposed as META on macOS

SDL Commits
1 
From acd719c5aade255fc1dd4428ae39a9f1cf6de76c Mon Sep 17 00:00:00 2001
From: David Gow <[EMAIL REDACTED]>
Date: Thu, 10 Jun 2021 17:23:01 +0800
Subject: [PATCH] The Command key should be exposed as META on macOS

SDL 1.2 uses {L,R}META for the Command key on macOS. It uses {L,R}SUPER
for the windows logo key on Windows/Linux. SDL 2.0 maps both of these to
{L,R}GUI. Just select between them at compile time.
---
 src/SDL12_compat.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/SDL12_compat.c b/src/SDL12_compat.c
index c05a60e..d795ae1 100644
--- a/src/SDL12_compat.c
+++ b/src/SDL12_compat.c
@@ -2414,11 +2414,19 @@ Scancode20toKeysym12(const SDL_Scancode scancode20)
     CASESCANCODE20TOKEY12(LCTRL,LCTRL);
     CASESCANCODE20TOKEY12(LSHIFT,LSHIFT);
     CASESCANCODE20TOKEY12(LALT,LALT);
+#ifdef __MACOSX__
+    CASESCANCODE20TOKEY12(LGUI,LMETA);
+#else
     CASESCANCODE20TOKEY12(LGUI,LSUPER);
+#endif
     CASESCANCODE20TOKEY12(RCTRL,RCTRL);
     CASESCANCODE20TOKEY12(RSHIFT,RSHIFT);
     CASESCANCODE20TOKEY12(RALT,RALT);
+#ifdef __MACOSX__
+    CASESCANCODE20TOKEY12(RGUI,RMETA);
+#else
     CASESCANCODE20TOKEY12(RGUI,RSUPER);
+#endif
 
     CASESCANCODE20TOKEY12(MODE,MODE);
     #undef CASESCANCODE20TOKEY12