$OpenBSD: patch-configure_ac,v 1.2 2013/12/07 10:47:21 sthen Exp $
--- configure.ac.orig	Sat Nov 30 13:56:05 2013
+++ configure.ac	Wed Dec  4 14:34:28 2013
@@ -3185,6 +3185,14 @@ 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 \
