[I18n-sig] UCS-4 configuration

[Martin v. Loewis]

> Are there any open issues left?  A list of those would help!  Some I
> can think of:
> 
> - Marc-Andre's message
> - disable Unicode entirely with a configuration switch
> - documentation
> - marshalling UCS2 strings containing lone surrogates
> 
> Anything else?

- bump the API version? With the current CVS, this is only necessary
  for systems with a 4-byte wchar_t.
- Find some magic to deal with exchanging extensions across
  incompatible installation.
- fix UTF-8 encoding for lone surrogates, as per SF bug report.
- Windows configuration: should unicodeobject.h provide
  autoconfiguration, or should everything be defined in PC/config.h
  (or similar manually-maintained config files).

I'll be leaving for two weeks next week, so I can tackle larger tasks
only later.

On the PYD compatibility, the easiest solution would be to create a
Py_InitModule5, which also takes a flag value, this flag value could
include other incompatible settings, such as --without-cycle-gc. Of
course, such a change would break all existing binary modules, unless
Python continues to provide Py_InitModule4 to binary modules. Calling
Py_InitModule4 would then imply narrow Unicode.

To hack without Py_InitModule5, putting flags into PYTHON_API_VERSION
might also work.

Regards,
Martin