diff --git a/configure.ac b/configure.ac
index 61a00d9..ff424e8 100755
--- a/configure.ac
+++ b/configure.ac
@@ -5,7 +5,7 @@
 ##  Copyright (c) 1996, 97, 98, 99, 2000 Kunihiro Ishiguro <kunihiro@zebra.org>
 ##  Portions Copyright (c) 2003 Paul Jakma <paul@dishone.st>
 ##
-## $Id: configure.ac,v 1.86 2005/01/12 16:52:55 ajs Exp $
+## $Id: configure.ac,v 1.87 2005/01/12 17:27:27 ajs Exp $
 AC_PREREQ(2.53)
 
 AC_INIT(Quagga, 0.98.0, [http://bugzilla.quagga.net])
@@ -1107,6 +1107,11 @@
 fi
 AC_SUBST(LIBCAP)
 
+dnl -------------------
+dnl test for ucontext.h
+dnl -------------------
+AC_CHECK_HEADERS(ucontext.h)
+
 dnl ---------------------------
 dnl check for glibc 'backtrace'
 dnl ---------------------------