$OpenBSD: patch-configure_ac,v 1.7 2013/05/25 12:33:05 sthen Exp $
--- configure.ac.orig	Mon May 20 12:50:55 2013
+++ configure.ac	Sat May 25 12:08:28 2013
@@ -3166,6 +3166,14 @@ if test "x$squid_host_os" = "xmingw" ; then
   ac_cv_func_statfs='yes'
 fi
 
+dnl Some systems (mostly BSDs) require -lexecinfo for backtrace_symbols_fd()
+AC_CHECK_LIB(execinfo,backtrace_symbols_fd,[BACKTRACE_LIB="-lexecinfo"])
+oLIBS=$LIBS
+LIBS="$BACKTRACE_LIB"
+AC_CHECK_FUNCS(backtrace_symbols_fd)
+LIBS=$oLIBS
+AC_SUBST(BACKTRACE_LIB)
+
 dnl Check for library functions
 AC_CHECK_FUNCS(\
 	backtrace_symbols_fd \
