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/include/Makefile.am b/include/Makefile.am
index e0c1a2b..4e92d55 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -31,6 +31,7 @@
                        osmocom/core/macaddr.h \
                        osmocom/core/msgb.h \
                        osmocom/core/panic.h \
+                       osmocom/core/prbs.h \
                        osmocom/core/prim.h \
                        osmocom/core/process.h \
                        osmocom/core/rate_ctr.h \