Revision 111983

- general config: adjust Apache/TestConfig.pm not to write irrelevant
  httpd.conf sections (e.g. <IfModule prefork.c> for win32, and vice
  versa, A-T knows exactly what mpm it needs to write the config for).
  Thus reducing the clutter.

- winnt case: Apache/TestConfig.pm config for <IfModule mpm_winnt.c>
  before Apache-2.0.50 ThreadsPerChild had to be at least as big as
  the number of Vhosts. This was fixed in 2.0.50. Since A-T knows the
  httpd version, it shouldn't start so many threads for httpd >=
  2.0.50, but @MinClients@. Also add BACK_COMPAT_MARKER in the logic
  so when no longer support httpd < 2.0.50, this logic could be removed.