SDL: Always enable D3D12 GPU on Windows

SDL Commits
1 
From ef54c3bf183b60da50ad4417bbab142ce4c4754f Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Tue, 29 Apr 2025 08:51:26 -0700
Subject: [PATCH] Always enable D3D12 GPU on Windows

This isn't dependent on the render subsystem

Fixes https://github.com/libsdl-org/SDL/issues/12922
---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b7b86aaeefb14..db0eb1cadbd5f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3023,7 +3023,7 @@ if(SDL_GPU)
     set(SDL_GPU_D3D11 1)
     set(HAVE_SDL_GPU TRUE)
   endif()
-  if(SDL_RENDER_D3D12)
+  if(WINDOWS)
     sdl_glob_sources("${SDL3_SOURCE_DIR}/src/gpu/d3d12/*.c")
     set(SDL_GPU_D3D12 1)
     set(HAVE_SDL_GPU TRUE)