merge this feature into 2.0.46-dev:

     mod_log_config: Add the ability to log the id of the thread
     processing the request via new %P formats.

Reviewed by:    stoddard, nd


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@99820 13f79535-47bb-0310-9956-ffa450edef68