split libgb into a separate library for outside use

This also removes the dependency to osmo_sock() inside libcommon and
replaces it with osmo_sock_* from libosmocore
diff --git a/openbsc/include/osmocom/gprs/Makefile.am b/openbsc/include/osmocom/gprs/Makefile.am
new file mode 100644
index 0000000..fe5714e
--- /dev/null
+++ b/openbsc/include/osmocom/gprs/Makefile.am
@@ -0,0 +1,3 @@
+libgb_HEADERS = gprs_bssgp.h gprs_ns.h gprs_ns_frgre.h
+
+libgbdir = $(includedir)/osmocom/gprs
diff --git a/openbsc/include/openbsc/gprs_bssgp.h b/openbsc/include/osmocom/gprs/gprs_bssgp.h
similarity index 99%
rename from openbsc/include/openbsc/gprs_bssgp.h
rename to openbsc/include/osmocom/gprs/gprs_bssgp.h
index df93f5b..bfc7d33 100644
--- a/openbsc/include/openbsc/gprs_bssgp.h
+++ b/openbsc/include/osmocom/gprs/gprs_bssgp.h
@@ -143,6 +143,8 @@
 
 /* Our implementation */
 
+#include <osmocom/gsm/gsm48.h>
+
 /* gprs_bssgp_util.c */
 extern struct gprs_ns_inst *bssgp_nsi;
 struct msgb *bssgp_msgb_alloc(void);
diff --git a/openbsc/include/openbsc/gprs_ns.h b/openbsc/include/osmocom/gprs/gprs_ns.h
similarity index 100%
rename from openbsc/include/openbsc/gprs_ns.h
rename to openbsc/include/osmocom/gprs/gprs_ns.h
diff --git a/openbsc/include/openbsc/gprs_ns_frgre.h b/openbsc/include/osmocom/gprs/gprs_ns_frgre.h
similarity index 100%
rename from openbsc/include/openbsc/gprs_ns_frgre.h
rename to openbsc/include/osmocom/gprs/gprs_ns_frgre.h