Still lacks docs for Windows (anyone?).

This fixes a regression compared to 2.x, where sys.modules.items()
returns a copy, as indicated by a comment in the source.  Diagnosis and
patch by Erik Tollerud.

It was already the case with Python 2.  However, the corresponding
sys module entries are now set to None (instead of an unusable file object).

Initial patch by Sjoerd de Vries.

Issue #13444: When stdout has been closed explicitly, we should not attempt to flush it at shutdown and print an error.

This also adds a test for issue #5319, whose resolution introduced the issue.

Issue #12856: Ensure child processes do not inherit the parent's random seed for filename generation in the tempfile module.
Patch by Brian Harring.

mention of the CPython optimization hack.

Issue #13458: Fix a memory leak in the ssl module when decoding a certificate with a subjectAltName.
Patch by Robert Xiao.

an invalid integer value.

TLS key only if the thread that called fork() had an associated auto thread
state (this might not be the case for example for a thread created outside of
Python calling into a subinterpreter).

POSIX semaphores (among which FreeBSD < 8).

 * Add tests for PyUnicode_EncodeDecimal() and PyUnicode_TransformDecimalToASCII()
 * Remove the unused "e" variable in replace()

raised when the wrapped raw file is non-blocking and the write would block.
Previous code assumed that the raw write() would raise BlockingIOError, but
RawIOBase.write() is defined to returned None when the call would block.
Patch by sbt.

Patch written by Arfrever Frehtes Taifersar Arahesis.

This allows compiling extension modules with -Wswitch-enum on gcc.
Initial patch by Floris Bruynooghe.