2/2: fixup: add osmo_gsup_peer_id with type enum and union

During code review it was requested to insert an ability to handle different
kinds of peer id, in order to be able to add a Global Title in the future.

Add this, but only in the publicly visible API. For osmo-hlr internal code, I
intend to push implementing this into the future, when a different peer
identification actually gets introduced.

This way we don't need to implement it now in all osmo-hlr code paths (save
time now), but still make all API users aware that this type may be extended in
the future.

Change-Id: Ide9dcdca283ab989240cfc6e53e9211862a199c5
diff --git a/src/gsupclient/Makefile.am b/src/gsupclient/Makefile.am
index 38b1582..a8674e4 100644
--- a/src/gsupclient/Makefile.am
+++ b/src/gsupclient/Makefile.am
@@ -9,7 +9,7 @@
 lib_LTLIBRARIES = libosmo-gsup-client.la
 
 libosmo_gsup_client_la_SOURCES = \
-	ipa_name.c \
+	gsup_peer_id.c \
 	gsup_client.c \
 	gsup_req.c \
 	$(NULL)