* d-demangle.c (enum dlang_symbol_kinds): Remove enum.
(struct dlang_info): New struct
(dlang_decode_backref): New function.
(dlang_backref): New function.
(dlang_symbol_backref): New function.
(dlang_type_backref): New function.
(dlang_symbol_name_p): New function.
(dlang_function_type_noreturn): New function.
(dlang_function_type): Add 'info' parameter. Decode function type
with dlang_function_type_noreturn.
(dlang_function_args): Add 'info' parameter.
(dlang_type): Add 'info' parameter. Handle back referenced types.
(dlang_identifier): Replace 'kind' parameter with 'info'. Handle back
referenced symbols. Split off decoding of plain identifiers to...
(dlang_lname): ...here.
(dlang_parse_mangle): Replace 'kind' parameter with 'info'. Decode
function type and return with dlang_type.
(dlang_parse_qualified): Replace 'kind' parameter with 'info', add
'suffix_modifier' parameter. Decode function type with
dlang_function_type_noreturn.
(dlang_parse_tuple): Add 'info' parameter.
(dlang_template_symbol_param): New function.
(dlang_template_args): Add 'info' parameter. Decode symbol parameter
with dlang_template_symbol_param. Handle back referenced values, and
externally mangled parameters.
(dlang_parse_template): Add 'info' parameter.
(dlang_demangle_init_info): New function.
(dlang_demangle): Initialize and pass 'info' parameter.
* testsuite/d-demangle-expected: Add new tests.