* configure.in: Convert to autoconf script.  Blow away lots
	of now-redundant Makefile fragments.
	* configure: Generate using Autoconf.
	* Makefile.tpl: Rewrite to reflect autoconfiscation.
	* Makefile.in: Regenerate.
(config)
	* acx.m4: New.
	* mh-a68bsd, mh-aix386, mh-apollo68, mh-delta88, mh-hp300,
	mh-hpux, mh-hpux8, mh-irix5, mh-irix6, mh-ncrsvr43, mh-openedition,
	mh-riscos, mh-sysv: Delete.
	* mh-cxux, mh-dgux386, mh-interix, mh-lynxrs6k, mh-ncr3000,
	mh-necv4, mh-sco, mh-solaris, mh-sysv4, mh-sysv5, mt-v810: Simplify.