Improved udev to warn when one of our rules will overwrite one from upstream

filesystem/udev/udev.conf

@@ -61,6 +61,11 @@ udev_rules() {
 
 	echo "Installing .rules files..."
 
+	# check for possible conflicts
+	for x in etc/udev/rules.d/*.rules; do
+		[ ! -e "$confdir/rules/${x##*/}" ] || echo_warning "${x##*/}: ours will overwrite theirs."
+	done
+
 	mkdir -p "$rulesd"
 	for x in $( ls -1 etc/udev/rules.d/*.rules $confdir/rules/*.rules 2> /dev/null ); do
 		install -v -m 644 $x $rulesd/