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/Makefile.am b/src/Makefile.am
index 5ae94e4..3838a5a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -5,9 +5,9 @@
 TRAU_LIBVERSION=4:0:2
 
 AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)
-AM_CFLAGS= -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOVTY_CFLAGS) $(COVERAGE_CFLAGS)
+AM_CFLAGS= -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOVTY_CFLAGS) $(LIBOSMOE1D_CFLAGS) $(COVERAGE_CFLAGS)
 AM_LDFLAGS = $(COVERAGE_LDFLAGS)
-COMMONLIBS = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOVTY_LIBS)
+COMMONLIBS = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOVTY_LIBS) $(LIBOSMOE1D_LIBS)
 
 lib_LTLIBRARIES = libosmoabis.la libosmotrau.la
 
@@ -19,6 +19,7 @@
 			 ipa_proxy.c \
 			 subchan_demux.c \
 			 trau_frame.c \
+			 input/e1d.c \
 			 input/ipa.c \
 			 input/ipa_keepalive.c \
 			 input/ipaccess.c \