SDL_gpu_shadercross: Fix segfault on no output path

SDL Commits
1 
From 934c9a591189eee72ca02017ff43ea8b645b8784 Mon Sep 17 00:00:00 2001
From: cosmonaut <[EMAIL REDACTED]>
Date: Fri, 25 Oct 2024 11:53:59 -0700
Subject: [PATCH] Fix segfault on no output path

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

diff --git a/src/cli.c b/src/cli.c
index 825310e..0098abe 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -179,6 +179,11 @@ int main(int argc, char *argv[])
         print_help();
         return 1;
     }
+    if (!outputFilename) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "%s: missing output path", argv[0]);
+        print_help();
+        return 1;
+    }
     fileData = SDL_LoadFile(filename, &fileSize);
     if (fileData == NULL) {
         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Invalid file (%s)", SDL_GetError());