This patch lets modules append themselves to SERVER_SUBVERSION at

configure time without interfering with other modules doing the same. It
is used like this in .module files or CONFIG_START/END sections:

 SUBVERSION="$SUBVERSION mymodule/123"

At present multiple modules adding themselves to the version string get
confused, causing compile warnings and ending up with only one module in
the version. Module authors using -DSERVER_SUBVERSION in their $CFLAGS
will have to make a slight modification to the above format instead. This
will only affect modules designed for 1.3 betas.

Reviewed by:	Dean Gaudet, Ralf S. Engelschall, Ken Coar


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@80447 13f79535-47bb-0310-9956-ffa450edef68