add 'osmo-auc-gen' tool that can be used to generate auth vectors

Thsi tool usses libosmocore in order to generate 2G and 3G
authentication vectors from private key material, exactly like an AuC
would produce them in a real network.
diff --git a/utils/Makefile.am b/utils/Makefile.am
index 22903d9..4e7869e 100644
--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -1,7 +1,10 @@
 if ENABLE_UTILITIES
 INCLUDES = $(all_includes) -I$(top_srcdir)/include
-noinst_PROGRAMS = osmo-arfcn
+noinst_PROGRAMS = osmo-arfcn osmo-auc-gen
 
 osmo_arfcn_SOURCES = osmo-arfcn.c
 osmo_arfcn_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gsm/libosmogsm.la
+
+osmo_auc_gen_SOURCES = osmo-auc-gen.c
+osmo_auc_gen_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gsm/libosmogsm.la
 endif