gdb/

    * d-lang.h (d_parse_symbol): Add declaration.
    * d-lang.c (extract_identifiers)
    (extract_type_info): Remove functions.
    (parse_call_convention, parse_attributes)
    (parse_function_types, parse_function_args)
    (parse_type, parse_identifier, call_convention_p)
    (d_parse_symbol): New functions.
    (d_demangle): Use d_parse_symbol to demangle D symbols.

gdb/testsuite/

    * gdb.dlang/demangle.exp: New file.
gdb/

    * d-lang.c (parse_call_convention)
    (parse_attributes, parse_function_types)
    (parse_function_args, parse_type, parse_identifier)
    (call_convention_p, d_parse_symbol): Move functions to ...
    * d-support.c: ... New file.
Testing D expression parsing