Fix the location of device lock files.

Use the new semi-standard device lock file directory on GNU/Linux.  This is
nescessary on (at least) Arch Linux and Parabola GNU/Linux.

http://lists.freedesktop.org/archives/systemd-devel/2011-March/001823.html

--- RXTX.orig/src/SerialImp.h
+++ RXTX/src/SerialImp.h
@@ -109,7 +109,7 @@
 /*  Ports known on the OS */
 #if defined(__linux__)
 #	define DEVICEDIR "/dev/"
-#	define LOCKDIR "/var/lock"
+#	define LOCKDIR "/run/lock/lockdev"
 #	define LOCKFILEPREFIX "LCK.."
 #	define FHS
 #endif /* __linux__ */