Add a compat version of backtrace()/backtrace_symbols() written by

Maxim Sobolev <sobomax@FreeBSD.org>



git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@4056 d4fa192b-c00b-0410-8231-f00ffab90ce4

lib/libvarnishcompat/Makefile.am

@@ -9,6 +9,7 @@ libvarnishcompat_la_LDFLAGS = -version-info 1:0:0
 libvarnishcompat_la_SOURCES = \
 	asprintf.c \
 	daemon.c \
+	execinfo.c \
 	vasprintf.c \
 	setproctitle.c \
 	srandomdev.c \