SDL: Fixed warning: this function declaration is not a prototype

SDL Commits
1 
From fca2f5318906f527e23d634432f3ff2979140f10 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Mon, 18 Sep 2023 13:09:28 -0700
Subject: [PATCH] Fixed warning: this function declaration is not a prototype

---
 src/video/SDL_sysvideo.h | 2 +-
 src/video/SDL_video.c    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/video/SDL_sysvideo.h b/src/video/SDL_sysvideo.h
index ee45fa1e9180..0d55708a94f0 100644
--- a/src/video/SDL_sysvideo.h
+++ b/src/video/SDL_sysvideo.h
@@ -544,7 +544,7 @@ extern void SDL_OnWindowFocusGained(SDL_Window *window);
 extern void SDL_OnWindowFocusLost(SDL_Window *window);
 extern void SDL_OnWindowDisplayChanged(SDL_Window *window);
 extern void SDL_UpdateWindowGrab(SDL_Window *window);
-extern SDL_Window *SDL_GetToplevelForKeyboardFocus();
+extern SDL_Window *SDL_GetToplevelForKeyboardFocus(void);
 
 extern SDL_bool SDL_ShouldAllowTopmost(void);
 
diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index 8b0cce97ef08..fbd63a8c0227 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -3561,7 +3561,7 @@ void SDL_OnWindowFocusLost(SDL_Window *window)
     }
 }
 
-SDL_Window *SDL_GetToplevelForKeyboardFocus()
+SDL_Window *SDL_GetToplevelForKeyboardFocus(void)
 {
     SDL_Window *focus = SDL_GetKeyboardFocus();