Fix `install-includes' sub-target of `install' target in top-level

Makefile.tmpl: The umask+cp approach didn't work as expected (especially for
users which extracted the distribution under 'umask 077'), so replace it by an
explicit cp+chmod approach.

Submitted by: Richard Lloyd, Curt Sampson
Reviewed and fixed by: Ralf S. Engelschall
PR: 2656, 2626


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@81820 13f79535-47bb-0310-9956-ffa450edef68