SDL: Don't center the mouse when gaining focus unless we're using relative mode warping

SDL Commits
1 
From 1c5b3e0e1655e94ffafc21d4b1c6087e5217c40b Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Fri, 15 Oct 2021 18:12:18 -0700
Subject: [PATCH] Don't center the mouse when gaining focus unless we're using
 relative mode warping

This is necessary now that we actually change the mouse position when calling SDL_WarpMouseInWindow() in relative mode.
---
 src/video/SDL_video.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index 07c7aa5eac..371a6e54cf 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -2897,7 +2897,9 @@ SDL_OnWindowFocusGained(SDL_Window * window)
 
     if (mouse && mouse->relative_mode) {
         SDL_SetMouseFocus(window);
-        SDL_WarpMouseInWindow(window, window->w/2, window->h/2);
+        if (mouse->relative_mode_warp) {
+            SDL_WarpMouseInWindow(window, window->w/2, window->h/2);
+        }
     }
 
     SDL_UpdateWindowGrab(window);