bpo-31828: make Py_tss_NEEDS_INIT usable in non-static initialisers

[scoder]

Without the cast, the compound literal is not accepted as a regular RHS value of an assignment.

https://bugs.python.org/issue25658

[ma8ma]

Sadly, the compound literals is not compatible with C++ standard 😣 (it's a C99 feature)
A similar issue of the C-API header was pointed out at related #1362 (comment).

[scoder]

Ok, then ... should we just distinguish the C and C++ cases? And maybe even MSVC from the real compilers, as usual?

I mean, this is a public header file. It's fairly annoying if it constrains the applicability of its definitions. I guess I'll have to open a new ticket for this one after all...

[ma8ma]

FYI, we've solved an initialization issue of a TSS key by using temporary variables. #1362 (comment)

cpython/Python/pystate.c

Lines 49 to 54 in 731e189

	/* A TSS key must be initialized with Py_tss_NEEDS_INIT
	in accordance with the specification. */
	{
	Py_tss_t initial = Py_tss_NEEDS_INIT;
	runtime->gilstate.autoTSSkey = initial;
	}

[iritkatriel]

https://bugs.python.org/issue25658 is closed. What is the status of this PR?