Builder for sendmail.cf's, in particular freebsd.cf.

This needs to be revisited - we need a simple way of building/installing
these at runtime from the installed system's /etc/mail directory.
freebsd.mc,v and freefall.mc,v have been repository copied here.

etc/sendmail/Makefile

@@ -0,0 +1,49 @@
+#	@(#)Makefile	8.19 (Berkeley) 1/14/97
+#	$Id$
+
+M4=	m4
+CFDIR=	${.CURDIR}/../../contrib/sendmail/cf
+CHMOD=	chmod
+ROMODE=	444
+RM=	rm -f
+
+.SUFFIXES:  .mc .cf
+
+.mc.cf:
+	$(RM) ${.TARGET}
+	(cd ${.CURDIR} && \
+	    $(M4) -D_CF_DIR_=${CFDIR}/ ${CFDIR}/m4/cf.m4 ${@:R}.mc) > ${.TARGET}
+	$(CHMOD) $(ROMODE) ${.TARGET}
+
+ALL=	freebsd.cf
+
+# Local sendmail.cf, may be set in /etc/make.conf.  Warning! If set, this
+# causes 'make install' to always copy it over /etc/sendmail.cf!!!
+# Caveat emptor!  Be sure you want this before you enable it.
+.if defined(SENDMAIL_CF)
+ALL+=	${SENDMAIL_CF}
+.endif
+
+CLEANFILES+=$(ALL)
+
+all: $(ALL)
+
+depend:
+
+install:
+.if defined(SENDMAIL_CF)
+	${INSTALL} ${COPY} -o ${BINOWN} -g ${BINGRP} -m 644 ${SENDMAIL_CF} \
+		${DESTDIR}/etc/sendmail.cf
+.endif
+
+# Helper for src/etc/Makefile
+etc-sendmail.cf: freebsd.cf
+	${INSTALL} ${COPY} -o ${BINOWN} -g ${BINGRP} -m 644 freebsd.cf \
+		${DESTDIR}/etc/sendmail.cf
+
+# this is overkill, but....
+M4FILES!= find ${CFDIR} -type f -name '*.m4' -print
+
+$(ALL):  $(M4FILES)
+
+.include <bsd.prog.mk>