SDL: wayland: handle 0 extra buttons in message box

SDL Commits
1 
From 1e7c7c69c5e658c0b80b3f8ee050f5c3c8c0b513 Mon Sep 17 00:00:00 2001
From: Marcin Serwin <[EMAIL REDACTED]>
Date: Mon, 4 Nov 2024 18:09:50 +0100
Subject: [PATCH] wayland: handle 0 extra buttons in message box

When no extra buttons are passed to zenity with `--question --switch`
arguments it fails to show anything, however, SDL3 still reports
success. To handle this case, we pass an additional "OK" button.
---
 src/video/wayland/SDL_waylandmessagebox.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/video/wayland/SDL_waylandmessagebox.c b/src/video/wayland/SDL_waylandmessagebox.c
index c0c37f9a098ec..88a860b03f3f9 100644
--- a/src/video/wayland/SDL_waylandmessagebox.c
+++ b/src/video/wayland/SDL_waylandmessagebox.c
@@ -146,6 +146,9 @@ bool Wayland_ShowMessageBox(const SDL_MessageBoxData *messageboxdata, int *butto
             argv[argc++] = "--extra-button=\"\"";
         }
     }
+    if (messageboxdata->numbuttons == 0) {
+        argv[argc++] = "--extra-button=OK";
+    }
     argv[argc] = NULL;
 
     SDL_PropertiesID props = SDL_CreateProperties();