bpo-32430: Rename Modules/Setup.dist to Modules/Setup
Remove the necessity to copy the former manually to the latter when updating the local source tree.
They can be exposed when some C API calls fail due to lack of
memory.
* Failed Py_BuildValue() could cause an assertion error in the
following TextIOWrapper.tell().
* input_chunk could be decrefed twice in TextIOWrapper.seek()
after failed Py_BuildValue().
* initvalue could leak in StringIO.__getstate__() after failed
PyDict_Copy().
* `flags` is indeed deprecated, but there is a validation on its value for
backwards compatibility reasons. This adds mention of this in the docs.
* The docs say that `sizehint` is deprecated and ignored, but it is still
used when `epoll_create1()` is unavailable. This adds mention of this in
the docs.
* `sizehint=-1` is acceptable again, and is replaced with `FD_SETSIZE-1`.
This is needed to have a default value available at the Python level,
since `FD_SETSIZE` is not exposed to Python. (see: bpo-31938)
* Reject `sizehint=0` since it is invalid to pass on to `epoll_create()`.
The relevant tests have also been updated.
* Fix also PyInit__gdbm() to catch errors.
* test.pythoninfo: add gdbm.version
* test_dbm_gnu now logs GDBM_VERSION when run in verbose mode.
* pythoninfo: rename function to collect_gdbm()
bpo-33671
* use memoryview() with size == file size on Windows, see https://github.com/python/cpython/pull/7160#discussion_r195405230
* release intermediate (sliced) memoryview immediately
* replace "OSX" occurrences with "macOS"
* add some unittests for copyfileobj()
