[PATCH] Speedup first memmem match

[Florian Weimer]

* Rajalakshmi Srinivasaraghavan:

> 2018-08-24  Rajalakshmi Srinivasaraghavan  <raji@linux.vnet.ibm.com>
>
> 	* string/memmem.c: Use memcmp for first match.

Change looks goot to me.  Thanks.