[Python-3000] patch: bytes object PyBUF_LOCKDATA read-only and immutable support

[Greg Ewing]

Guido van Rossum wrote:

> 0 -> 1 -> 2 -> ... (SIMPLE or WRITABLE get)
> ... -> 2 -> 1 -> ... (SIMPLE or WRITABLE release)
> 0 -> -1 (LOCKDATA get)
> -1 -> 0 (LOCKDATA release)

And if this is the correct interpretation, the requests
should be called something like READ_LOCK and WRITE_LOCK
to make this clear.

--
Greg