This both fixes D demangling in GDB and updates it to the current D
mangling spec.

2014-01-07  Iain Buclaw  <ibuclaw@gdcproject.org>

    gdb/

        * d-lang.h (d_parse_symbol): Add declaration.
        * d-lang.c (extract_identifiers)
        (extract_type_info): Remove functions.
        (d_demangle): Use d_parse_symbol implemented in d-support.c to
        demangle D symbols.
        * d-support.c: New file.

    gdb/testsuite/

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

---