Preserve existing installation directories. We copy over binaries,

the build directory, the headers, and the man pages.  Everything else,
the config, htdocs, manual, error, icons, and cgi directories are
not installed if the directories already exist.  I got sick of having
to re-edit printenv for my tests, and this is the same logic 1.3 used.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@95911 13f79535-47bb-0310-9956-ffa450edef68