split 'libosmocore' from openbsc codebase

This library is intended to collect all generic/common funcitionality
of all Osmocom.org projects, including OpenBSC but also OsmocomBB

The library currently includes the following modules:

bitvec, comp128, gsm_utils, msgb, select, signal, statistics, talloc, timer,
tlv_parse, linuxlist

msgb allocation error debugging had to be temporarily disabled as it depends on
'debug.c' functionality which at the moment remains in OpenBSC
diff --git a/openbsc/src/gsm_subscriber_base.c b/openbsc/src/gsm_subscriber_base.c
index 0570061..dee89c0 100644
--- a/openbsc/src/gsm_subscriber_base.c
+++ b/openbsc/src/gsm_subscriber_base.c
@@ -27,11 +27,10 @@
 #include <string.h>
 #include <assert.h>
 
-#include <openbsc/talloc.h>
+#include <osmocore/talloc.h>
 #include <openbsc/gsm_subscriber.h>
 #include <openbsc/paging.h>
 #include <openbsc/debug.h>
-#include <openbsc/paging.h>
 
 LLIST_HEAD(active_subscribers);
 void *tall_subscr_ctx;