Suppress gcc 15 unterminated-string-initialization warnings

	Drop an ignored attribute
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	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

Non-ASCII code are often warned by localized compilers.

Introduce Universal Parser mode for the parser.
This commit includes these changes:

* Introduce `UNIVERSAL_PARSER` macro. All of CRuby related functions
  are passed via `struct rb_parser_config_struct` when this macro is enabled.
* Add CI task with 'cppflags=-DUNIVERSAL_PARSER' for ubuntu.

Previously, it was supported in prelude.c, but has not followed up the
builtin-loader system.

[Misc #18891]