SDL: include: Always declare SDL_GDKSuspendComplete.

From f7580374a1c0664d05466f6415bf21d584463121 Mon Sep 17 00:00:00 2001
From: Ethan Lee <[EMAIL REDACTED]>
Date: Fri, 20 Dec 2024 13:14:55 -0500
Subject: [PATCH] include: Always declare SDL_GDKSuspendComplete.

This is always defined in the symbol table and the function safely does nothing
on non-GDK targets, so treat it like any other SDL_system function.
---
 include/SDL3/SDL_main.h | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/SDL3/SDL_main.h b/include/SDL3/SDL_main.h
index fca557e5d74fe..d51977b63f01e 100644
--- a/include/SDL3/SDL_main.h
+++ b/include/SDL3/SDL_main.h
@@ -567,17 +567,16 @@ extern SDL_DECLSPEC void SDLCALL SDL_UnregisterApp(void);
 
 #endif /* defined(SDL_PLATFORM_WINDOWS) */
 
-#ifdef SDL_PLATFORM_GDK
-
 /**
  * Callback from the application to let the suspend continue.
  *
+ * This function is only needed for Xbox GDK support; all other platforms will
+ * do nothing and set an "unsupported" error message.
+ *
  * \since This function is available since SDL 3.1.3.
  */
 extern SDL_DECLSPEC void SDLCALL SDL_GDKSuspendComplete(void);
 
-#endif /* SDL_PLATFORM_GDK */
-
 #ifdef __cplusplus
 }
 #endif