+AC_CHECK_HEADER([net/if_packet.h],
+ [HAVE_IF_PACKET=yes],
+ [HAVE_IF_PACKET=no])
+AM_CONDITIONAL([HAVE_IF_PACKET], [test "$HAVE_IF_PACKET" = yes])
+if test "$HAVE_IF_PACKET" = yes; then
+ AC_DEFINE([HAVE_IF_PACKET], [1],
+ [Define to 1 if net/if_packet.h is available.])
+fi
+
+AC_ARG_ENABLE(
+ [ssl],
+ [AC_HELP_STRING([--enable-ssl],
+ [Enable ssl support (requires libssl)])],
+ [case "${enableval}" in # (
+ yes) ssl=true ;; # (
+ no) ssl=false ;; # (
+ *) AC_MSG_ERROR([bad value ${enableval} for --enable-ssl]) ;;
+ esac],
+ [ssl=false])
+
+if test "$ssl" = true; then
+dnl Make sure that pkg-config is installed.
+m4_pattern_forbid([PKG_CHECK_MODULES])