Merge r1729235, r1730079, r1801665 from trunk:

Merge r1729235, r1730079, r1801665 from trunk:

Exclude MPM modules from automatic LoadModule
enabling when configure was called with
-enable-load-all-modules. The default MPM
should still get enabled automatically.

Use different variables to track normal
modules and MPMs during build.

Normal modules and MPMs follow different
rules in the config, e.g. we are only
allowed to have one active LoadModule
for an MPM in the config.

As a side effect, LoadModule for MPMs
will now come before LoadModule for
the normal modules.

Makefile.in: fix MPM_MODULES typo
Submitted by: rjung, jchampion
Reviewed by: jchampion, icing, ylavic

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1808854 13f79535-47bb-0310-9956-ffa450edef68