GPU: support JSON config

src/modules/gpu/gpu.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#define FF_GPU_MODULE_NAME "GPU"
+
+void ffPrintGPU(FFinstance* instance, FFGPUOptions* options);
+void ffInitGPUOptions(FFGPUOptions* options);
+bool ffParseGPUCommandOptions(FFGPUOptions* options, const char* key, const char* value);
+void ffDestroyGPUOptions(FFGPUOptions* options);
+
+#ifdef FF_HAVE_JSONC
+#include "common/jsonconfig.h"
+void ffParseGPUJsonObject(FFinstance* instance, json_object* module);
+#endif