* call.c (can_convert): Allow user-defined conversions.
	(can_convert_standard): New.
	* cp-tree.h: Declare it.
	* cvt.c (convert_to_reference): Use it.
	* pt.c (convert_nontype_argument): Likewise.
	* search.c (check_final_overrider): Likewise.
	Don't worry about user-defined conversions.

From-SVN: r200937