Merge r1491155 from trunk:

Allow use of strtoul()

It conforms to C89 and we don't support older compilers than that.

PR: 55077

Submitted by: sf
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1494121 13f79535-47bb-0310-9956-ffa450edef68