* mangle.c (DECL_TEMPLATE_ID_P): Remove.
(CLASSTYEP_TEMPLATE_ID_P): Check template info, and context when
ascertaining primaryness.
(G): Remove template_args.
(decl_is_template_id): New function.
(write_encoding): Use decl_is_template_id.
(write_name): Likewise. Handle type_decls. Get main variant of
type decls.
(write_nested_name): Likewise.
(write_prefix): Likewise.
(write_template_prefix): Likewise.
(write_special_name_constructor): Remove defunct production from
comment.
(write_bare_function_type): Remove comment about absent parameter.
(write_template_template_arg): Add missing grammar production to
comment.