Exclude gpoptutils when checking loadable libraries

The gpoptutils module was removed during the 5.0 development cycle
and won't be available in the new cluster. Add exception for upgrades
from 4.3.

contrib/pg_upgrade/function.c

@@ -224,11 +224,22 @@ get_loadable_libraries(migratorContext *ctx)
 	PGresult  **ress;
 	int			totaltups;
 	int			dbnum;
+	char	   *pg83_str;
 
 	ress = (PGresult **)
 		pg_malloc(ctx, active_cluster->dbarr.ndbs * sizeof(PGresult *));
 	totaltups = 0;
 
+	/*
+	 * gpoptutils was removed during the 5.0 development cycle and the
+	 * functionality is now in backend, skip when checking for loadable
+	 * libraries in 4.3->5.0 upgrades.
+	 */
+	if (GET_MAJOR_VERSION(ctx->old.major_version) <= 802)
+		pg83_str = "probin NOT IN ('$libdir/gpoptutils') AND ";
+	else
+		pg83_str = "";
+
 	/* Fetch all library names, removing duplicates within each DB */
 	for (dbnum = 0; dbnum < active_cluster->dbarr.ndbs; dbnum++)
 	{
@@ -240,8 +251,10 @@ get_loadable_libraries(migratorContext *ctx)
 										"SELECT DISTINCT probin "
 										"FROM	pg_catalog.pg_proc "
 										"WHERE	prolang = 13 /* C */ AND "
-									 "		probin IS NOT NULL AND "
+										"		probin IS NOT NULL AND "
+										"		%s "
 										"		oid >= %u;",
+										pg83_str,
 										FirstNormalObjectId);
 		totaltups += PQntuples(ress[dbnum]);