Add pseudo-random bit sequence generator to libosmcoore

These PRBS sequences are specified in ITU-T O.150.  They are typically
used as test data to be transmitted for BER (bit error rate) testing.

Change-Id: I227b6a6e86a251460ecb816afa9a7439d5fb94d1
diff --git a/src/Makefile.am b/src/Makefile.am
index d8fceca..8e7ef4b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -21,7 +21,7 @@
 			 conv.c application.c rbtree.c strrb.c \
 			 loggingrb.c crc8gen.c crc16gen.c crc32gen.c crc64gen.c \
 			 macaddr.c stat_item.c stats.c stats_statsd.c prim.c \
-			 conv_acc.c conv_acc_generic.c sercomm.c
+			 conv_acc.c conv_acc_generic.c sercomm.c prbs.c
 
 if HAVE_SSE3
 libosmocore_la_SOURCES += conv_acc_sse.c