(pushdecl): Use lookup_name_current_level_global instead of lookup_name for extern...

(pushdecl): Use lookup_name_current_level_global instead of lookup_name for extern references.

(pushdecl): Use lookup_name_current_level_global instead
of lookup_name for extern references.  Don't return duplicate decl
if it came from the global binding level, and there exists a
conflicting decl in an intervening block.
(lookup_name_current_level_global); New function.

From-SVN: r7189