Use crypt_r() when available instead of crypt() in the crypt module.

As a nice side effect: This also avoids a memory sanitizer flake as clang msan doesn't know about crypt's internal libc allocated buffer.
(cherry picked from commit 387512c7ecde6446f2e29408af2e16b9fc043807)

Co-authored-by: Gregory P. Smith <greg@krypto.org> [Google]

Rename our new MEMORY_SANITIZER define to _Py_MEMORY_SANITIZER.
Project based C Preprocessor namespacing at its finest. :P
(cherry picked from commit 3015fb8ce4d25603434b9b44bb7effb98a481532)

Co-authored-by: Gregory P. Smith <greg@krypto.org>

Adds configure flags for msan and ubsan builds to make it easier to enable.
These also encode the detail that address sanitizer and memory sanitizer
should disable pymalloc.

Define MEMORY_SANITIZER when appropriate at build time and adds workarounds
to existing code to mark things as initialized where the sanitizer is otherwise unable to
determine that.  This lets our build succeed under the memory sanitizer.  not all tests
pass without sanitizer failures yet but we're in pretty good shape after this.

(cherry picked from commit 1584a0081500d35dc93ff88e5836df35faf3e3e2)

Co-authored-by: Gregory P. Smith <greg@krypto.org> [Google LLC]

glibc is deprecating libcrypt in favor of libxcrypt, however python assumes
that crypt.h will always be included. This change makes the header inclusion
explicit when libxcrypt is present on the system.

* Remove Setup.config
* Always define WITH_THREAD for compatibility.

Windows buildbots started failing due to include-related errors.

* group the (stateful) runtime globals into various topical structs
* consolidate the topical structs under a single top-level _PyRuntimeState struct
* add a check-c-globals.py script that helps identify runtime globals

Other globals are excluded (see globals.txt and check-c-globals.py).

PEP 432 specifies a number of large changes to interpreter startup code, including exposing a cleaner C-API. The major changes depend on a number of smaller changes. This patch includes all those smaller changes.