mtp-hotplug: support outputting HWDB files.

- Output new udev hardware database style files
  Using -w option.
- Makefile.am: generate hwdb files by default
- configure.ac: udev rules live in /usr/lib/udev usually these days
diff --git a/Makefile.am b/Makefile.am
index c6d46c2..7b7e06b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -10,15 +10,22 @@
 # build and ship it on Linux.
 if USE_LINUX
 udevrulesdir=@UDEV@/rules.d
+hwdbdir=@UDEV@/hwdb.d
 udevrules_DATA=@UDEV_RULES@
+hwdb_DATA=69-libmtp.hwdb
 noinst_DATA=libmtp.usermap libmtp.fdi
 
 libmtp.usermap: util/mtp-hotplug
 	util/mtp-hotplug > libmtp.usermap
+
 @UDEV_RULES@: util/mtp-hotplug
 	util/mtp-hotplug -u -p"@UDEV@" @UDEV_GROUP@ @UDEV_MODE@ > @UDEV_RULES@
+
 libmtp.fdi: util/mtp-hotplug
 	util/mtp-hotplug -H > libmtp.fdi
 
-CLEANFILES = libmtp.usermap @UDEV_RULES@ libmtp.fdi
+$(hwdb_DATA): util/mtp-hotplug
+	util/mtp-hotplug -w > $(hwdb_DATA)
+
+CLEANFILES = libmtp.usermap @UDEV_RULES@ libmtp.fdi libmtp.hwdb
 endif