Method terminal_is_available

source/matplot/backend/gnuplot.cpp:335–339

    }

    bool gnuplot::terminal_is_available(std::string_view term) {
        std::string msg = run_and_get_output("gnuplot -e \"set terminal " +
                                     std::string(term.data()) + "\" 2>&1");
        return msg.empty();
    }

    std::tuple<int, int, int> gnuplot::gnuplot_version() {
        static std::tuple<int, int, int> version{0, 0, 0};