SDL: Clear any previous errors if we successfully show a message box

SDL Commits
1 
From 552bee47cb23267b90dee422de0b6fdf20fb8453 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Fri, 27 Oct 2023 10:11:00 -0700
Subject: [PATCH] Clear any previous errors if we successfully show a message
 box

---
 src/video/SDL_video.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index d68c88700476..eec3e0dd8797 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -4945,6 +4945,8 @@ int SDL_ShowMessageBox(const SDL_MessageBoxData *messageboxdata, int *buttonid)
         if (!*error) {
             SDL_SetError("No message system available");
         }
+    } else {
+        SDL_ClearError();
     }
 
     (void)SDL_AtomicDecRef(&SDL_messagebox_count);