-AC_ARG_ENABLE(threads, AC_HELP_STRING([--enable-threads],
- [enable threading support]), [enable_threads=${enableval}])
-
-AC_ARG_ENABLE(loopback, AC_HELP_STRING([--enable-loopback],
- [enable loopback support]), [enable_loopback=${enableval}])
-AM_CONDITIONAL(LOOPBACK, test "${enable_loopback}" = "yes")
-
-AC_ARG_ENABLE(ethernet, AC_HELP_STRING([--enable-ethernet],
- [enable Ethernet support]), [enable_ethernet=${enableval}])
-AM_CONDITIONAL(ETHERNET, test "${enable_ethernet}" = "yes")
-
-AC_ARG_ENABLE(wifi, AC_HELP_STRING([--enable-wifi],
- [enable WiFi support]), [enable_wifi=${enableval}])
-if (test "${enable_wifi}" = "yes"); then
+AC_ARG_ENABLE(threads,
+ AC_HELP_STRING([--enable-threads], [enable threading support]),
+ [enable_threads=${enableval}], [enable_threads="no"])
+
+AC_ARG_ENABLE(loopback,
+ AC_HELP_STRING([--enable-loopback], [enable loopback support]),
+ [enable_loopback=${enableval}], [enable_loopback="no"])
+AM_CONDITIONAL(LOOPBACK, test "${enable_loopback}" != "no")
+AM_CONDITIONAL(LOOPBACK_BUILTIN, test "${enable_loopback}" = "builtin")
+
+AC_ARG_ENABLE(ethernet,
+ AC_HELP_STRING([--enable-ethernet], [enable Ethernet support]),
+ [enable_ethernet=${enableval}], [enable_ethernet="no"])
+AM_CONDITIONAL(ETHERNET, test "${enable_ethernet}" != "no")
+AM_CONDITIONAL(ETHERNET_BUILTIN, test "${enable_ethernet}" = "builtin")
+
+AC_ARG_ENABLE(wifi,
+ AC_HELP_STRING([--enable-wifi], [enable WiFi support]),
+ [enable_wifi=${enableval}], [enable_wifi="no"])
+if (test "${enable_wifi}" != "no"); then