Patch from Alex Gaynor.

Patch by Charles-Axel Dein.

Patch from Donald Stufft.

This is basically a backport of issues #9003 and #22366.

The backport currently doesn't achieve anything since the function isn't used (yet).

daemon threads run while the interpreter is shutting down; instead,
these threads are now killed when they try to take the GIL), as it seems
to break some existing code.

The backport of ensurepip to 2.7.9 allows pip to optionally be installed
or upgraded using the bundled pip provided by the new ensurepip module.
The option can be specified persistently using the configure option:

    ./configure --with-ensurepip[=upgrade|install|no]

It can also be overridden on either the "install" or "altinstall" targets:

    make [alt]install ENSUREPIP=[upgrade|install|no]

For Python 2, the default option is "no" (do not install pip).

Warn against the use of leaking macro PyObject_REPR().