2005-01-12 Andrew J. Schorr <ajschorr@alumni.princeton.edu>

	* configure.ac: Test for header file <ucontext.h> (for use in
	  signal processing).
	* sigevent.c: (trap_default_signals) Use the SA_SIGINFO flag to
	  pass additional siginfo_t and ucontext_t arguments to core_handler
	  and exit_handler.
	  (core_handler,exit_handler) Now invoked with 3 arguments (using
	  SA_SIGINFO).  Pass additional info to zlog_signal.
	  (program_counter) New function to find program counter in ucontext_t,
	  needs to be enhanced to support more platforms (currently works only
	  on Linux/x86).
	* log.h: Change the zlog_signal prototype to add new arguments
	  siginfo_t * and program_counter.
	* log.c: (zlog_signal) Add new arguments siginfo and program_counter.
	  Include si_addr and program counter (if non-NULL) in message.
	  And remove #ifdef HAVE_GLIBC_BACKTRACE around hex_append, since
	  that is now used to render the si_addr and PC pointers.
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 ---------------------------