+AC_SUBST(api)
+AC_SUBST(req)
+AC_SUBST(visibility)
+
+api=""
+req=""
+use_asio=""
+
+
+# configure flags
+AC_ARG_ENABLE(debug, [AS_HELP_STRING([--enable-debug],[enable various debug output])])
+AC_ARG_WITH(jack, [AS_HELP_STRING([--with-jack], [choose JACK server support (mac and linux only)])])
+AC_ARG_WITH(alsa, [AS_HELP_STRING([--with-alsa], [choose native ALSA API support (linux only)])])
+AC_ARG_WITH(pulse, [AS_HELP_STRING([--with-pulse], [choose PulseAudio API support (linux only)])])
+AC_ARG_WITH(oss, [AS_HELP_STRING([--with-oss], [choose OSS API support (unixes)])])
+AC_ARG_WITH(core, [AS_HELP_STRING([--with-core], [choose CoreAudio API support (mac only)])])
+AC_ARG_WITH(asio, [AS_HELP_STRING([--with-asio], [choose ASIO API support (win32 only)])])
+AC_ARG_WITH(ds, [AS_HELP_STRING([--with-ds], [choose DirectSound API support (win32 only)])])
+AC_ARG_WITH(wasapi, [AS_HELP_STRING([--with-wasapi], [choose Windows Audio Session API support (win32 only)])])