SDL_gpu_shadercross: Fix segfault when D3DCompile is not found

SDL Commits
1 
From 7fb4b66e0ce714946e84f10a8480bdc1ad22a4f8 Mon Sep 17 00:00:00 2001
From: cosmonaut <[EMAIL REDACTED]>
Date: Mon, 28 Oct 2024 15:42:09 -0700
Subject: [PATCH] Fix segfault when D3DCompile is not found

---
 src/SDL_gpu_shadercross.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/SDL_gpu_shadercross.c b/src/SDL_gpu_shadercross.c
index c39fc1a..d0e7c25 100644
--- a/src/SDL_gpu_shadercross.c
+++ b/src/SDL_gpu_shadercross.c
@@ -607,6 +607,11 @@ static ID3DBlob *SDL_ShaderCross_INTERNAL_CompileDXBC(
     ID3DBlob *errorBlob;
     HRESULT ret;
 
+    if (SDL_D3DCompile == NULL) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "%s", "Could not load D3DCompile!");
+        return NULL;
+    }
+
     ret = SDL_D3DCompile(
         hlslSource,
         SDL_strlen(hlslSource),