mkconfig: start deprecating Makefile config targets

Now that we've got boards.cfg and most people have converted over,
start warning people who have yet to so we can phase board configs
completely out of the Makefile.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

doc/feature-removal-schedule.txt

@@ -7,6 +7,22 @@ file.
 
 ---------------------------
 
+What:	boards with xxx_config targets in top level Makefile
+When:	Release v2012.03
+
+Why:	We have a boards.cfg file which the vast majority of boards have
+	converted over to.  Boards that still manually run mkconfig in the
+	top level Makefile are either dead, or the maintainer doesn't care,
+	or they are doing something weird/wrong that should be fixed in a
+	different way, or they need to extend boards.cfg syntax (unlikely).
+
+	In any case, if no one cares about these boards to figure out how
+	to make boards.cfg work, then we'll just punt them.
+
+Who:	Mike Frysinger <vapier@gentoo.org>
+
+---------------------------
+
 What:	CONFIG_NET_MULTI option
 When:	Release 2009-11
 

mkconfig

@@ -29,6 +29,15 @@ if [ \( $# -eq 2 \) -a \( "$1" = "-A" \) ] ; then
 	set ${line}
 	# add default board name if needed
 	[ $# = 3 ] && set ${line} ${1}
+elif [ "${MAKEFLAGS+set}${MAKELEVEL+set}" = "setset" ] ; then
+	# only warn when using a config target in the Makefile
+	cat <<-EOF
+
+	warning: Please migrate to boards.cfg.  Failure to do so will
+	         mean removal of your board in the next release.
+
+	EOF
+	sleep 5
 fi
 
 while [ $# -gt 0 ] ; do