SDL: wayland: Wayland_Vulkan_GetInstanceExtensions didn't set the count variable.

SDL Commits
1 
From 780b6612a925abb5c2c2020c44c2a54f53100801 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sat, 4 Nov 2023 14:53:24 -0400
Subject: [PATCH] wayland: Wayland_Vulkan_GetInstanceExtensions didn't set the
 count variable.

Fixes #8468.
---
 src/video/wayland/SDL_waylandvulkan.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/video/wayland/SDL_waylandvulkan.c b/src/video/wayland/SDL_waylandvulkan.c
index 3e372bd2a66a..b07aaf95e895 100644
--- a/src/video/wayland/SDL_waylandvulkan.c
+++ b/src/video/wayland/SDL_waylandvulkan.c
@@ -118,12 +118,16 @@ void Wayland_Vulkan_UnloadLibrary(SDL_VideoDevice *_this)
     }
 }
 
-char const* const* Wayland_Vulkan_GetInstanceExtensions(SDL_VideoDevice *_this,
-                                              Uint32 *count)
+char const* const* Wayland_Vulkan_GetInstanceExtensions(SDL_VideoDevice *_this, Uint32 *count)
 {
     static const char *const extensionsForWayland[] = {
         VK_KHR_SURFACE_EXTENSION_NAME, VK_KHR_WAYLAND_SURFACE_EXTENSION_NAME
     };
+
+    if (count) {
+        *count = SDL_arraysize(extensionsForWayland);
+    }
+
     return extensionsForWayland;
 }