Add a new make knob, SENDMAIL_MC, which is meant to replace SENDMAIL_CF as

users should be configuring via m4 now.  If set, use m4 to create the .cf
file.  Also, if either SENDMAIL_MC or SENDMAIL_CF is set, 'make install' or
'make distribution' in src/etc/sendmail/ will install the appropriate .cf as
/etc/mail/sendmail.cf.  This fixes some mergemaster problems.

PR:		conf/13016

etc/defaults/make.conf

@@ -324,6 +324,14 @@ BDECFLAGS=	-W -Wall -ansi -pedantic -Wbad-function-cast -Wcast-align \
 #
 #
 # sendmail
+#
+# The following sets the default m4 configuration file to use at
+# install time.  Use with caution as a make install will overwrite
+# any existing /etc/mail/sendmail.cf.  Note that SENDMAIL_CF is now
+# deprecated.
+#
+#SENDMAIL_MC=freebsd.mc
+#
 # Setting the following variables modifes the build environment for
 # sendmail and its related utilities. For example, SASL support can be
 # added with settings such as:

etc/sendmail/Makefile

@@ -17,11 +17,20 @@ RM=	rm -f
 
 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/mail/sendmail.cf!!!
+# Local SENDMAIL_MC or SENDMAIL_CF may be set in /etc/make.conf.
+# Warning! If set, this causes 'make install' to always copy it
+# over /etc/mail/sendmail.cf!!!
 # Caveat emptor!  Be sure you want this before you enable it.
+.if defined(SENDMAIL_MC)
+INSTALL_CF=	${SENDMAIL_MC:R}.cf
+.else
 .if defined(SENDMAIL_CF)
-ALL+=	${SENDMAIL_CF}
+INSTALL_CF=	${SENDMAIL_CF}
+.endif
+.endif
+
+.if defined(INSTALL_CF)
+ALL+=	${INSTALL_CF}
 .endif
 
 CLEANFILES+=$(ALL)
@@ -30,22 +39,37 @@ all: $(ALL)
 
 depend:
 
-install:
-.if defined(SENDMAIL_CF)
-	${INSTALL} ${COPY} -o ${BINOWN} -g ${BINGRP} -m 644 ${SENDMAIL_CF} \
+.if defined(INSTALL_CF)
+install: ${INSTALL_CF}
+.if (defined(SENDMAIL_MC) && defined(SENDMAIL_CF))
+	@echo ">>> ERROR: Both SENDMAIL_CF and SENDMAIL_MC can not be set"
+	@false
+.endif
+	${INSTALL} ${COPY} -o ${BINOWN} -g ${BINGRP} -m 644 ${INSTALL_CF} \
 		${DESTDIR}/etc/mail/sendmail.cf
+.else
+install:
 .endif
 
 # Helper for src/etc/Makefile
 distribution: freebsd.cf freebsd.mc
+.if (defined(SENDMAIL_MC) && defined(SENDMAIL_CF))
+	@echo ">>> ERROR: Both SENDMAIL_CF and SENDMAIL_MC can not be set"
+	@false
+.endif
 	${INSTALL} ${COPY} -o ${BINOWN} -g ${BINGRP} -m 644 ${.CURDIR}/freebsd.mc \
 		${DESTDIR}/etc/mail/freebsd.mc
 	${INSTALL} ${COPY} -o ${BINOWN} -g ${BINGRP} -m 644 freebsd.cf \
 		${DESTDIR}/etc/mail/freebsd.cf
+.if defined(INSTALL_CF)
+	${INSTALL} ${COPY} -o ${BINOWN} -g ${BINGRP} -m 644 ${INSTALL_CF} \
+		${DESTDIR}/etc/mail/sendmail.cf
+.else
 	${INSTALL} ${COPY} -o ${BINOWN} -g ${BINGRP} -m 644 freebsd.cf \
 		${DESTDIR}/etc/mail/sendmail.cf
-	${INSTALL} -c -o ${BINOWN} -g ${BINGRP} -m 644 /dev/null \ 
-		${DESTDIR}/var/log/sendmail.st 
+.endif
+	${INSTALL} -c -o ${BINOWN} -g ${BINGRP} -m 644 /dev/null \
+	    ${DESTDIR}/var/log/sendmail.st
 
 # this is overkill, but....
 M4FILES!= find ${CFDIR} -type f -name '*.m4' -print

share/examples/etc/make.conf

@@ -324,6 +324,14 @@ BDECFLAGS=	-W -Wall -ansi -pedantic -Wbad-function-cast -Wcast-align \
 #
 #
 # sendmail
+#
+# The following sets the default m4 configuration file to use at
+# install time.  Use with caution as a make install will overwrite
+# any existing /etc/mail/sendmail.cf.  Note that SENDMAIL_CF is now
+# deprecated.
+#
+#SENDMAIL_MC=freebsd.mc
+#
 # Setting the following variables modifes the build environment for
 # sendmail and its related utilities. For example, SASL support can be
 # added with settings such as:

share/man/man5/make.conf.5

@@ -468,6 +468,14 @@ support.
 Set to disable the installation of
 .Xr ppp 8
 as an suid root program.
+.It Va SENDMAIL_MC
+.Vt ( str )
+The default m4 configuration file to use at install time.
+Use with caution as a make install will overwrite any existing
+.Pa /etc/mail/sendmail.cf .
+Note that
+.Va SENDMAIL_CF
+is now deprecated.
 .It Va SENDMAIL_CFLAGS
 .Vt ( str )
 Flags to pass to the compile command when building