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/libosmocore/include/osmocore/utils.h b/libosmocore/include/osmocore/utils.h
new file mode 100644
index 0000000..198f45a
--- /dev/null
+++ b/libosmocore/include/osmocore/utils.h
@@ -0,0 +1,6 @@
+#ifndef OSMOCORE_UTIL_H
+#define OSMOCORE_UTIL_H
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+#endif