e1d: Initial osmo-e1d support

osmo-e1d is part of the Osmocom 'software defined E1 interface,
which consists of a USB device for the actual E1 hardware interfacing,
and a daemon (osmo-e1d) implementing a libusb-based driver.

This commit adds initial support for talking to osmo-e1d using
the related libosmoe1d library.  You need to use '--enable-e1d'
at configure time to enable it.

Change-Id: Ia0431c124e3b5b4108aee7b109d8c4bb0d8b45d4
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/src/e1_input.c b/src/e1_input.c
index a707438..cb1612d 100644
--- a/src/e1_input.c
+++ b/src/e1_input.c
@@ -890,6 +890,9 @@
 #ifdef HAVE_DAHDI_USER_H
 	e1inp_dahdi_init();
 #endif
+#ifdef ENABLE_E1D
+	e1inp_e1d_init();
+#endif
 	e1inp_ipaccess_init();
 	e1inp_rs232_init();
 	e1inp_unixsocket_init();