[Issue 18865] Add x86 SIMD Intrinsics to druntime

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18865

--- Comment #7 from ponce <aliloko at gmail.com> ---
(In reply to Jack Stouffer from comment #4)
> I don't see why we couldn't do the same thing for Intel intrinsics.

Because it's a ton of work, hence why compiler writers did provide "builtins"
but not "intrinsics".

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