diff --git a/configure.ac b/configure.ac
index 2ea3ed7..aa74fc3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-# $Id: configure.ac,v 1.437 2010/01/17 20:48:22 tim Exp $
+# $Id: configure.ac,v 1.438 2010/01/18 01:05:39 tim Exp $
 #
 # Copyright (c) 1999-2004 Damien Miller
 #
@@ -15,7 +15,7 @@
 # OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 AC_INIT(OpenSSH, Portable, openssh-unix-dev@mindrot.org)
-AC_REVISION($Revision: 1.437 $)
+AC_REVISION($Revision: 1.438 $)
 AC_CONFIG_SRCDIR([ssh.c])
 
 AC_CONFIG_HEADER(config.h)
@@ -744,6 +744,7 @@
 	;;
 # UnixWare 7.x, OpenUNIX 8
 *-*-sysv5*)
+	CPPFLAGS="$CPPFLAGS -Dvsnprintf=_xvsnprintf -Dsnprintf=_xsnprintf"
 	AC_DEFINE(UNIXWARE_LONG_PASSWORDS, 1, [Support passwords > 8 chars])
 	AC_DEFINE(USE_PIPES)
 	AC_DEFINE(SETEUID_BREAKS_SETUID)