Include <strings.h> if we have it to get protos for strcase* on AIX.

Submitted by:	Victor J. Orlikowski <vjo@raleigh.ibm.com>
Reviewed by:	Jeff Trawick


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85965 13f79535-47bb-0310-9956-ffa450edef68