Merge r1609680, r1609688, r1641381, r1826289, r1826313, r1878467, r1878994, r1879000...

Merge r1609680, r1609688, r1641381, r1826289, r1826313, r1878467, r1878994, r1879000, r1879001, r1879002, r1879361 from trunk:

mod_proxy: add ap_proxy_define_match_worker() and use it for ProxyPassMatch
and ProxyMatch section to distinguish between normal workers and workers
with regex substitutions in the name. Implement handling of such workers
in ap_proxy_get_worker(). PR 43513

mod_proxy: better check for worker->s->is_name_matchable

Return a match whenever we get to the end of the worker name, regardless
of whether there is URL left.

ProxyPassMatch had been using the default worker in trunk.

Follow up to r1609680: simpler/faster ap_proxy_strcmp_ematch().

No functional change.

Follow up to r1609680: further simplify/optimize ap_proxy_strcmp_ematch().

While at it, same treatment for its mother ap_strcmp_match().

make sure the $n of the regular expressions is not included the name of the worker.
for example,  the example:
ProxyPassMatch "^(/.*\.gif)$" "http://backend.example.com:8000$1"
was giving:
AH00526: Syntax error on line nnn of bla/conf/httpd.conf:
ProxyPass Unable to parse URL: http://backend.example.com:8000$1

ap_proxy_define_match_worker: don't copy the url unnecessarily.

And save a few cycles, when the duplication is needed, by not copying
the ignored part.

ap_proxy_define_match_worker: disable connection reuse by default.

To avoid compat issues with dns/connection reuse now that a worker with
dollar substitution can be elected.

CHANGES entry for ap_proxy_define_match_worker().

Oups, axe spurious copypasta.

mod_proxy: unfail mixed ProxyPass/<Proxy> and ProxyPassMatch/<ProxyMatch>.

It is not a failure in current 2.4.x, so to ease backport and to avoid compat
breakage simply warn about the second directive being ignored.

This commit can be reverted in trunk if we want next versions to fail in this
case.

[Reverted by r1879363]

Submitted by: jkaluza, covener, ylavic, ylavic, jfclere, ylavic, ylavic, ylavic, ylavic, ylavic
Reviewed by: ylavic, minfrin (with an MMN bump), jim (agree w/ minfrin)

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1880772 13f79535-47bb-0310-9956-ffa450edef68