Fix issue 20852: core.sys.posix.sys.wait missing definitions on FreeBSD

[sakhmatd]

Upon further testing with the Vibe.d test suite, it appears that the entire idtype_t
struct from sys/wait.h is required for some parts of eventcore to compile.
Thus, I reopened issue 20852.

This commit adds all of the missing id types.

After adding the missing id types, Vibe.d tests pass as intended.

I apologize for not testing the initial commit more thoroughly.

[dlang-bot]

Thanks for your pull request and interest in making D better, @sakhmatd! We are looking forward to reviewing it, and you should be hearing from a maintainer soon.
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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	20852	major	core.sys.posix.sys.wait missing definitions on FreeBSD

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + druntime#3115"