… [Backport #21497]

	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

ruby/etc@6668bfd42a

…rations

ruby/io-console@dd013030dd

…ions

ruby/io-wait@48309d7877

…arations

ruby/io-nonblock@70909f5362

…ions

ruby/openssl@b6f56c4540

(ruby/strscan#158)

- `have_func` includes "ruby.h" by default.
- include "ruby/re.h" where `rb_reg_onig_match` is declared.

ruby/strscan@1ac96f47e9

…ions

ruby/strscan@18c0a59b65

ruby/json@95fb084027