libhttpd.dsp: Fix Debug build mentioned by fuankg in

http://mail-archives.apache.org/mod_mbox/httpd-dev/201305.mbox/%3C519FC54E.901@apache.org%3E.

trunk patch: http://svn.apache.org/r1486490
Submitted by: gsmith
Reviewed by: jim, minfrin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1486937 13f79535-47bb-0310-9956-ffa450edef68