Index: unix/serial.c
===================================================================
--- unix/serial.c.orig
+++ unix/serial.c
@@ -126,6 +126,10 @@ const char serial_rcsid[] = "$Id: serial
 #include <sys/termiox.h>
 #endif
 
+#if HAVE_LOCKDEV
+#include <ttylock.h>
+#endif
+
 /* Get definitions for both O_NONBLOCK and O_NDELAY.  */
 #ifndef O_NDELAY
 #ifdef FNDELAY
@@ -623,6 +627,20 @@ fsserial_lockfile (flok, qconn)
 	z = zalc;
       }
 #else /* ! HAVE_QNX_LOCKFILES */
+#if HAVE_LOCKDEV
+      {
+	int rc;
+	
+	if (flok)
+	  rc = ttylock(qsysdep->zdevice);
+	else
+	  rc = ttyunlock(qsysdep->zdevice);
+	if (rc)
+	  ulog (LOG_ERROR, "tty%slock (%s): %s", flok?"":"un", qsysdep->zdevice, strerror (-rc));
+	fret = (rc == 0 ? TRUE : FALSE);
+	return fret;
+      }
+#else /* ! HAVE_LOCKDEV */
 #if ! HAVE_SVR4_LOCKFILES
       {
 	const char *zbase;
@@ -660,6 +678,7 @@ fsserial_lockfile (flok, qconn)
 	z = zalc;
       }
 #endif /* HAVE_SVR4_LOCKFILES */
+#endif /* ! HAVE_LOCKDEV */
 #endif /* ! HAVE_QNX_LOCKFILES */
     }
 
Index: Makefile.am
===================================================================
--- Makefile.am.orig
+++ Makefile.am
@@ -25,7 +25,7 @@ endif
 
 AM_CFLAGS = $(WARN_CFLAGS) $(UUDIRFLAGS)
 
-LDADD = unix/libunix.a uuconf/libuuconf.a lib/libuucp.a
+LDADD = unix/libunix.a uuconf/libuuconf.a lib/libuucp.a $(LOCKDEV_LIBS)
 
 UUHEADERS = uucp.h uudefs.h uuconf.h policy.h system.h sysdep.h getopt.h
 
Index: configure.in
===================================================================
--- configure.in.orig
+++ configure.in
@@ -787,4 +787,6 @@ else
  AC_SYS_LONG_FILE_NAMES
 fi
 dnl
+PKG_CHECK_MODULES([LOCKDEV], [lockdev], AC_DEFINE([HAVE_LOCKDEV],[1],[Define if you have lockdev]))
+dnl
 AC_OUTPUT(Makefile uuconf/Makefile lib/Makefile unix/Makefile)