Method spawn

src/ipc/process.cpp:28–36

{
public:
    int spawn(const std::string& new_exe_name, const fs::path& argv0_path, int& pid) override
    {
        return mp::SpawnProcess(pid, [&](int fd) {
            fs::path path = argv0_path;
            path.remove_filename();
            path /= fs::PathFromString(new_exe_name);
            return std::vector<std::string>{fs::PathToString(path), "-ipcfd", strprintf("%i", fd)};
        });
    }
    int waitSpawned(int pid) override { return mp::WaitProcess(pid); }
    bool checkSpawned(int argc, char* argv[], int& fd) override
    {