Function draw_next_frame

subprojects/llama.cpp/common/console.cpp:1073–1078

        static std::mutex mtx;
        static auto wait_time = std::chrono::milliseconds(100);
        static void draw_next_frame() {
            // don't need lock because only one thread modifies running
            frame = (frame + 1) % sizeof(LOADING_CHARS);
            replace_last(LOADING_CHARS[frame]);
            fflush(out);
        }
        void start() {
            std::unique_lock<std::mutex> lock(mtx);
            if (simple_io || running) {