append_arg
append_arg(&mnt_argv, execname);
append_arg(&mnt_argv, strdup(spec));
append_arg(&mnt_argv, strdup(name));
append_arg(&mnt_argv, NULL);
append_arg(a, p);
append_arg(a, p + 1);
append_arg(a, strdup("-o"));
append_arg(a, p);