手機 - F(x)tec Pro1 - Sailfish - 解決Undefined reference to stpcpy問題

參考資訊：
https://github.com/kdrag0n/proton_zf6/commit/cec73f0775526
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=5934637641c863cc2c1765a0d01c5b6f53ecc4fc

添加如下程式到lib/string.c

char *stpcpy(char *__restrict__ dest, const char *__restrict__ src);
char *stpcpy(char *__restrict__ dest, const char *__restrict__ src)
{
	while ((*dest++ = *src++) != '\0')
		/* nothing */;
	return --dest;
}
EXPORT_SYMBOL(stpcpy);