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/include/openbsc/gsm_04_80.h b/openbsc/include/openbsc/gsm_04_80.h
index c240bbe..266b5f7 100644
--- a/openbsc/include/openbsc/gsm_04_80.h
+++ b/openbsc/include/openbsc/gsm_04_80.h
@@ -123,7 +123,7 @@
 #define ASN1_IA5_STRING_TAG		0x16
 #define ASN1_UNICODE_STRING_TAG		0x1E
 
-#include <openbsc/msgb.h>
+#include <osmocore/msgb.h>
 
 #define MAX_LEN_USSD_STRING	31