libpam: provide a real /etc/pam.d/ftp

We provide both /etc/pam.d/ftp and /etc/pam.d/ftpd because FTP servers
are inconsistent about which service name they use.  Previously ftp was
a hard link to ftpd; to avoid hard linking config files, replace ftp
with a normal config file that includes the ftpd service.

Previously /etc/pam.d/ftpd was in the -ftp package, while /etc/pam.d/ftp
was in the -runtime package (by accident, not design).  Move both of
them to the -runtime package, where the rest of the pam.d services live,
since FTP servers from ports use it and people using a ports FTP server
might not want to to install the -ftp package as well.

This also fixes /etc/pam.d/ftp missing the @config tag.

Reviewed by:	des, bapt
Approved by:	des (mentor)
Differential Revision:	https://reviews.freebsd.org/D50339

lib/libpam/pam.d/Makefile

@@ -22,18 +22,15 @@ CRONPACKAGE=	cron
 
 .if ${MK_AT} != "no"
 CONFGROUPS+=	AT
-AT+=	atrun
+AT+=		atrun
 ATPACKAGE+=	at
 .endif
 
 .if ${MK_FTP} != "no"
 CONFGROUPS+=	FTP
-FTP+=	ftpd
-FTPPACKAGE=	ftp
-
-LINKMODE=	${CONFMODE}
-afterinstallconfig:
-	${INSTALL_LINK} ${TAG_ARGS} ${DESTDIR}${CONFDIR}/ftpd ${DESTDIR}${CONFDIR}/ftp
+FTP+=		ftp ftpd
+# Do not put these in the ftp package, since ports also use them.
+FTPPACKAGE=	runtime
 .endif
 
 .include <bsd.prog.mk>

lib/libpam/pam.d/ftp

@@ -0,0 +1,13 @@
+#
+# PAM configuration for the "ftp" service.  This is not used by the FreeBSD
+# ftpd(8), but is provided for compatibility with FTP servers from ports.
+#
+
+# auth
+auth		include		ftpd
+
+# account
+account		include		ftpd
+
+# session
+session		include		ftpd