filebuf.cc (filebuf::open): Call _IO_file_open if _G_HAVE_IO_FILE_OPEN is 1.

filebuf.cc (filebuf::open): Call _IO_file_open if _G_HAVE_IO_FILE_OPEN is 1.

        * filebuf.cc (filebuf::open): Call _IO_file_open if
        _G_HAVE_IO_FILE_OPEN is 1.
        * libio.h (_IO_fpos64_t, _IO_off64_t): Defined if
        _G_IO_IO_FILE_VERSION == 0x20001.
        * libioP.h (_IO_file_open): New declaration.
        * libio.h (_IO_FILE, _IO_stdin_, _IO_stdout_, _IO_stderr_,
        _IO_seekoff, _IO_seekpos): Add support for libio in egcs 2.1.
        * libioP.h (_IO_seekoff_t, _IO_seekpos_t, _IO_seek_t,
        _IO_seekoff, _IO_seekpos, _IO_default_seekoff,
        _IO_default_seekpos, _IO_default_seek, _IO_file_seekoff,
        _IO_file_seek, _IO_str_seekoff, _IO_pos_BAD, _IO_pos_as_off,
        _IO_pos_0): Ditto.
        * streambuf.h (streamoff, streampos): Ditto.
        * gen-params (__extension__): Use only if gcc version >= 2.8.

From-SVN: r17580