one small --with-module=foo:foo tweak

["William A. Rowe Jr." <wr...@rowe-clan.net>]

Playing with the --with-module=foo:foo feature Jim introduced last year,
I note that it can almost entirely build mod_foo.c into the server with no
supporting build files, except that Makefile.in is required.

The minimal contents of Makefile.in consists of <<<<

include $(top_srcdir)/build/special.mk

<<<<

Pretty straightforward.  Does anyone have the trick to get our ./configure
and --with-module=foo:foo logic to use that 'generic' .in by default?  That
would make it one step simpler to use this feature.