s_unpack_from to PyCFunction.

the right compiler flags.

- Following Guido's comments, renamed

  * pack_to -> pack_into
  * recv_buf -> recv_into
  * recvfrom_buf -> recvfrom_into

- Made fixes to _struct.c according to Neal Norwitz comments on the checkins
  list.

- Converted some ints into the appropriate -- I hope -- ssize_t and size_t.

2*sizeof(size_t) now, not 8.  This probably accounts for
current disasters on the 64-bit buildbot slaves.

to each allocated block.  This was using 4 bytes for each such
piece of info regardless of platform.  This didn't really matter
before (proof: no bug reports, and the debug-build obmalloc would
have assert-failed if it was ever asked for a chunk of memory
>= 2**32 bytes), since container indices were plain ints.  But after
the Py_ssize_t changes, it's at least theoretically possible to
allocate a list or string whose guts exceed 2**32 bytes, and the
PYMALLOC_DEBUG routines would fail then (having only 4 bytes
to record the originally requested size).

Now we use sizeof(size_t) bytes for each of a PYMALLOC_DEBUG
build's extra debugging fields.  This won't make any difference
on 32-bit boxes, but will add 16 bytes to each allocation in
a debug build on a 64-bit box.

not sure that's really standard compliant behaviour, but I guess
we have to fix that anyway...

Fix by renaming the variable.

In a different module, Neal fixed it by renaming _self to self.  There's
already a variable named 'self' here, so I used selfptr.

(I'm committing this on a Mac without Tk, but it's a simple search-and-replace.
<crosses fingers>, so  I'll watch the buildbots and see what happens.)

the output required more than one line.  "Small" dicts got
displayed in seemingly random order (the hash-induced order
produced by dict.__repr__).  None of this was documented.
Now pprint functions always sort dicts by key, and the docs
promise it.

This was proposed and agreed to during the PyCon 2006 core
sprint -- I just didn't have time for it before now.

Prevent an invalid memory read from test_coding in case the done flag is set.
In that case, the loop isn't entered.  I wonder if rather than setting
the done flag in the cases before the loop, if they should just exit early.

This code looks like it should be refactored.

Backport candidate (also the early break above if decoding_fgets fails)