gl_shader_disk_cache: Consider compressed size zero as an error

Co-Authored-By: ReinUsesLisp <reinuseslisp@airmail.cc>

src/video_core/renderer_opengl/gl_shader_disk_cache.cpp

@@ -59,7 +59,7 @@ std::vector<u8> CompressData(const T* source, std::size_t source_size) {
     const int compressed_size = LZ4_compress_default(reinterpret_cast<const char*>(source),
                                                      reinterpret_cast<char*>(compressed.data()),
                                                      source_size_int, max_compressed_size);
-    if (compressed_size < 0) {
+    if (compressed_size <= 0) {
         // Compression failed
         return {};
     }
@@ -649,4 +649,4 @@ std::string ShaderDiskCacheOpenGL::GetTitleID() const {
     return fmt::format("{:016X}", system.CurrentProcess()->GetTitleID());
 }
 
-} // namespace OpenGL
+} // namespace OpenGL
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