When setjmp/longjmp/exceptions are used on Windows it's necessary to store+restore additional information from the TEB.
I didn't find any official documentation about the values to be saved, but found the corresponding boost/context implemenataion:
abf8e04e23
This is similar to the special TIB handling on x86/x86_64 on Windows.
Without this fix an exception in a fiber segfaults without any output:
ruby -e "Fiber.new{ raise 'test' }.resume"
With `--std=c99` option coroutine/arm64/Context.h errs:
```
In file included from cont.c:26:
coroutine/arm64/Context.h:59:5: error: call to undeclared function 'asm'; ISO C99 and later do not support
implicit function declarations [-Wimplicit-function-declaration]
59 | asm ("hint #8;" : "+r"(r17) : "r"(r16));
| ^
```
Also move the common function header.
We don't need to save/restore x30 twice, and we can just use `ret`,
which uses x30 as return address register instead of explicit `ret <reg>`
instruction. This also allows us to use `autiasp` instead of `autia1716`
and we can skip setting SP/LR to x16/x17.
Also the size of register save area is shrunk by 16 bytes due to the
removal of extra x30 save/restore.
Saves comitters' daily life by avoid #include-ing everything from
internal.h to make each file do so instead. This would significantly
speed up incremental builds.
We take the following inclusion order in this changeset:
1. "ruby/config.h", where _GNU_SOURCE is defined (must be the very
first thing among everything).
2. RUBY_EXTCONF_H if any.
3. Standard C headers, sorted alphabetically.
4. Other system headers, maybe guarded by #ifdef
5. Everything else, sorted alphabetically.
Exceptions are those win32-related headers, which tend not be self-
containing (headers have inclusion order dependencies).
