(Partially) fix compilation for OpenBSD

[MBCX]

This (partially) fixes #92130, implementing most of the recommended fixes. This touches a lot of systems and even critical engine code variant.h which that was a best-guess fix and probably not the best solution (so any help there would be great, not al all experienced touching core engine code).

The TLDR of the fixes:

1. Simplified the bsd detection when needed (so that we don't have to specifically check for freebsd, or openbsd, or netbsd, etc.).
2. Disables the raycast module.
3. Mapped quick_exit to OpenBSD's _Exit where its used, see this comment.
4. Directly included input-event-codes.h from the Linux kernel. The rationale is that this saves us the hassle of having to figure out if the file is in the BSD variant and where (what I had to do for FreeBSD). Should be safe since the Wayland platform code is the only bit that uses it in all of Godot. Can't include GPL-v2 code.
5. Added missing platform detection for Jolt.
6. Prevented OpenBSD's "ambiguous error" failure in variant.h using type_traits.

Also, I could only get the export templates to compile, the compiler would crash compiling the file editor/editor_translation.cpp with a out of memory error. Not sure why.

[AThousandShips]

I'd say any fix should really be a complete one, especially if things depend on other, potentially controversial changes, or we risk going back and forth, at minimum the remaining fixes should have their own PR before this can be merged

[MBCX]

Well, if that's the case, I can easily cherry-pick the commits from those branches and integrate them into this one.

I did it this way because as I said, I had to touch third party code and critical engine code, so I thought maybe having them separated would be better overall and more focused.

[AThousandShips]

Keeping them as separate commits would be great! But it's hard to review an incomplete PR

[MBCX]

OK. I have merged all of the fixes into this branch for review.

[fire]

At some point upstream these changes to jolt.

[jrouwe]

See: jrouwe/JoltPhysics@41532dd

[fire]

Suggested change

	- License: GPL-2
	- License: GPL-2

We can't include GPL-2 code.

[Riteo]

Note that the header included has the GPL-2.0-only WITH Linux-syscall-note SPDX identifier. From what I can read that notes implies that system headers can be included with no issues and arguably, since these are all constants, this is permitted anyways. I do agree though that this entry could perhaps have some more clarification added.

https://spdx.org/licenses/Linux-syscall-note.html

NOTE! This copyright does not cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does not fall under the heading of "derived work". Also note that the GPL below is copyrighted by the Free Software Foundation, but the instance of code that it refers to (the Linux kernel) is copyrighted by me and others who actually wrote it.

Also note that the only valid version of the GPL as far as the kernel is concerned is this particular version of the license (ie v2, not v2.2 or v3.x or whatever), unless explicitly otherwise stated.

Linus Torvalds