Add mail500.m4 to source. Can be used to support sendmail

8.9 style configuration via MAILER(mail500).

clients/mail500/README

@@ -38,6 +38,8 @@ R$+%$+<@umich.edu>                 $>10$1%$2<@>
 R$+!$+<@umich.edu>                 $>10$1!$2<@>
 
 See the sample sendmail.cf in this directory for more details.
+For sendmail 8.9 (and later) users can use MAILER(mail500) if
+mail500.m4 is placed within sendmail's cf/mailer directory.
 
 The mail500 mailer should be defined similar to this in the
 sendmail.cf file:

clients/mail500/mail500.m4

+PUSHDIVERT(-1)
+#
+# mail500 mailer
+#
+# This file should be placed in the sendmail's cf/mailer directory.
+# To include this mailer in your .cf file, use the directive:
+#	MAILER(mail500)
+#
+
+#CQ foo.com
+
+POPDIVERT
+
+dnl
+ifdef(`MAIL500_HOST',
+	`define(`MAIL500_HOST_FLAG', `')',
+	`define(`MAIL500_HOST_FLAG', CONCAT(` -l ', CONCAT(MAIL500_HOST,` ')))')
+ifdef(`MAIL500_MAILER_PATH',,
+	`ifdef(`MAIL500_PATH',
+		`define(`MAIL500_MAILER_PATH', MAIL500_PATH)',
+		`define(`MAIL500_MAILER_PATH', /usr/local/libexec/mail500)')')
+ifdef(`MAIL500_MAILER_FLAGS',,
+	`define(`MAIL500_MAILER_FLAGS', `SmnXuh')')
+ifdef(`MAIL500_MAILER_ARGS',,
+	`define(`MAIL500_MAILER_ARGS',
+		CONCAT(`mail500',CONCAT(MAIL500_HOST_FLAG,`-f $f -h $h -m $n@$w $u')))')
+dnl
+MAILER_DEFINITIONS
+
+VERSIONID(`OpenLDAP mail500 981207')
+
+######################*****##############
+###   MAIL500 Mailer specification   ###
+##################*****##################
+
+Mmail500,	P=MAIL500_MAILER_PATH, F=CONCAT(`DFM', MAIL500_MAILER_FLAGS), S=11/31, R=20/40, T=DNS/RFC822/X-Unix,
+		ifdef(`MAIL500_MAILER_MAX', `M=500_MAILER_MAX, ')A=MAIL500_MAILER_ARGS
+
+PUSHDIVERT(3)
+# mail500 additions
+R$* < @ $=Q > $*	$#mail500 $@ $2 $: <$1>		domain handled by mail500
+POPDIVERT