[Bug #21931]

Keep tmp alive while RARRAY_CONST_PTR(tmp) is used by rb_str_format.

[alan: sunk the guard below usage]
Reviewed-by: Alan Wu <XrXr@users.noreply.github.com>

	search_nonascii(): Replace UB pointer cast with memcpy

	Casting a pointer to create an unaligned one is undefined behavior in C
	standards. Use memcpy to express the unaligned load instead to play by
	the rules.

	Practically, this yields the same binary output in many situations
	while fixing the crash in [Bug #21715].

	[PATCH] [Bug #21629] Enable `nonstring` attribute on clang 21

	[PATCH] [Bug #21629] Initialize `struct RString`

	[PATCH] [Bug #21629] Initialize `struct RArray`

	Suppress gcc 15 unterminated-string-initialization warnings

	Drop an ignored attribute
	MIME-Version: 1.0
	Content-Type: text/plain; charset=UTF-8
	Content-Transfer-Encoding: 8bit

	GCC 13.3.0 (Ubuntu 24.04) emits the following warning:

	../symbol.c: In function ‘rb_id_attrset’:
	../symbol.c:175:9: warning: ‘nonstring’ attribute ignored on objects of type ‘const char[][8]’ [-Wattributes]
	  175 |         RBIMPL_ATTR_NONSTRING() static const char id_types[][8] = {
	      |         ^~~~~~~~~~~~~~~~~~~~~

	Separate `__has_attribute` from `defined(__has_attribute)`

	Fix Visual C warnings:
	```
	regenc.h(121): warning C4067: unexpected tokens following preprocessor directive - expected a newline
	```

	Cast up `int` instruction code to `VALUE`

	Fix Visual C warnings:
	```
	iseq.c(3793): warning C4312: 'type cast': conversion from 'int' to 'void *' of greater size
	iseq.c(3794): warning C4312: 'type cast': conversion from 'int' to 'void *' of greater size
	```

	Do not let files depend on a phony target

	Detect `clock_gettime` and `clock_getres` for winpthreads

	[Bug #21380] Prohibit modification in String#split block

	Reported at https://hackerone.com/reports/3163876

	Fix a race condition with interned strings sweeping.

	[Bug #21172]

	This fixes a rare CI failure.

	The timeline of the race condition is:

	- A `"foo" oid=1` string is interned.
	- `"foo" oid=1` is no longer referenced and will be swept in the future.
	- Another `"foo" oid=2` string is interned.
	- `register_fstring` finds `"foo" oid=1`, but since it is about to be swept,
	  removes it from `fstring_table` and insert `"foo" oid=2` instead.
	- `"foo" oid=1` is swept, since it has the `RSTRING_FSTR` flag,
	  a `st_delete` is issued in `fstring_table` which removes `"foo" oid=2`.

	I don't know how to reproduce this bug consistently in a single test
	case.

	Check negative integer underflow

	Many of Oniguruma functions need valid encoding strings

[Bug #20585]

This was changed in 36a06efdd9f0604093dccbaf96d4e2cb17874dc8 because
`String.new(1024)` would end up allocating `1025` bytes, but the problem
with this change is that the caller may be trying to right size a String.

So instead, we should just better document the behavior of `capacity:`.

Co-authored-by: Jean Boussier <jean.boussier@gmail.com>

	[Bug #20322] Fix rb_enc_interned_str_cstr null encoding

	The documentation for `rb_enc_interned_str_cstr` notes that `enc` can be
	a null pointer, but this currently causes a segmentation fault when
	trying to autoload the encoding. This commit fixes the issue by checking
	for NULL before calling `rb_enc_autoload`.

	[Bug #20292] Truncate embedded string to new capacity