re PR c++/60642 (Unclear diagnostic with invalid use of abi_tag attribute on explicit...

re PR c++/60642 (Unclear diagnostic with invalid use of abi_tag attribute on explicit instantiation)

	PR c++/60642
	* decl2.c (is_late_template_attribute): Don't defer abi_tag.
	* mangle.c (write_unqualified_name): Fix abi_tag on templates.
	* pt.c (get_template_info): Handle NAMESPACE_DECL.
	(most_general_template): Handle more kinds of template.
	* tree.c (handle_abi_tag_attribute): Ignore abi_tag on template
	instantiations and specializations.

From-SVN: r208992