Resolve Metal compilation errors for sdcpp (#720)

otherarch/sdcpp/stable-diffusion.cpp

@@ -124,7 +124,7 @@ public:
 #endif
 #ifdef SD_USE_METAL
         LOG_DEBUG("Using Metal backend");
-        ggml_metal_log_set_callback(ggml_log_callback_default, nullptr);
+        ggml_backend_metal_log_set_callback(ggml_log_callback_default, nullptr);
         backend = ggml_backend_metal_init();
 #endif
 
@@ -1775,4 +1775,4 @@ SD_API sd_image_t* img2vid(sd_ctx_t* sd_ctx,
     LOG_INFO("img2vid completed in %.2fs", (t3 - t0) * 1.0f / 1000);
 
     return result_images;
-}
+}