Merge branch 'upstream' into concedo_experimental

# Conflicts:
#	.github/actions/windows-setup-curl/action.yml
#	.github/workflows/build-linux-cross.yml
#	README.md
#	common/CMakeLists.txt
#	examples/parallel/README.md
#	examples/parallel/parallel.cpp
#	ggml/src/ggml-sycl/element_wise.cpp
#	ggml/src/ggml-vulkan/CMakeLists.txt
#	tools/server/README.md

src/llama.cpp

@@ -168,6 +168,11 @@ static struct llama_model * llama_model_load_from_file_impl(
         struct llama_model_params params) {
     ggml_time_init();
 
+    if (!params.vocab_only && ggml_backend_reg_count() == 0) {
+        LLAMA_LOG_ERROR("%s: no backends are loaded. hint: use ggml_backend_load() or ggml_backend_load_all() to load a backend before calling this function\n", __func__);
+        return nullptr;
+    }
+
     unsigned cur_percentage = 0;
     if (params.progress_callback == NULL) {
         params.progress_callback_user_data = &cur_percentage;