re PR c++/18378 (ICE when returning a copy of a packed member)

re PR c++/18378 (ICE when returning a copy of a packed member)

	PR c++/18378
	* call.c (convert_like_real): Do not permit the use of a copy
	constructor to copy a packed field.

	PR c++/17413
	* decl.c (grokdeclarator): Return error_mark_node, not
	void_type_node, to indicate errors.
	* parser.c (cp_parser_template_parameter_list): Robustify.
	(cp_parser_template_parameter): Likewise.

	PR c++/19034
	* tree.c (cp_tree_equal): Handle OVERLOAD.

	PR c++/18378
	* g++.dg/ext/packed8.C: New test.

	PR c++/13268
	* g++.dg/template/crash31.C: New test.

	PR c++/19034
	* g++.dg/template/crash30.C: New test.

From-SVN: r92486