SDL: SDL_platform.h: define TARGET_OS_SIMULATOR as 0 if not already defined.

SDL Commits
1 
From 073cbc40cb7373ed65a0bbfcb49fd0db5f36a6d8 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Thu, 8 Jul 2021 21:20:02 +0300
Subject: [PATCH] SDL_platform.h: define TARGET_OS_SIMULATOR as 0 if not
 already defined.

c.f.: https://github.com/libsdl-org/SDL/issues/4475
---
 include/SDL_platform.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/SDL_platform.h b/include/SDL_platform.h
index b4e7b7f2f..1516da38c 100644
--- a/include/SDL_platform.h
+++ b/include/SDL_platform.h
@@ -87,6 +87,9 @@
 #ifndef TARGET_OS_TV
 #define TARGET_OS_TV 0
 #endif
+#ifndef TARGET_OS_SIMULATOR
+#define TARGET_OS_SIMULATOR 0
+#endif
 
 #if TARGET_OS_TV
 #undef __TVOS__