Merge r1653941, r1653978, r1656225 from trunk:

mod_alias: Introduce expression parser support for Alias, ScriptAlias
and Redirect.


Use unsigned bit fields.


mod_alias: follow up to r1653941.
Fill empty APLOGNO().

Submitted by: minfrin, ylavic
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1663259 13f79535-47bb-0310-9956-ffa450edef68