[Issue 24389] importC: Building zlib in Phobos with importC fails on FreeBSD 14

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24389

--- Comment #10 from Jonathan M Davis <issues.dlang at jmdavisProg.com> ---
(In reply to Iain Buclaw from comment #9)
> Alternatively, there's reverting the change that introduced using DMD to
> build zlib.

Yeah, I was talking about what would be required for zlib to build with
importC. Either way, ultimately, if we can't get dmd to work with importC and
the way that FreeBSD is using __asm__ in stdlib.h, then we can't build zlib in
Phobos with importC.

> If not resorting back to using $CC for FreeBSD, maybe the zlib sources could
> be altered to filter out the bad code in the header?
> 
> https://reviews.freebsd.org/source/src/browse/main/include/stdlib.h$347
> 
> #undef __generic?

Maybe? If it were done carefully, then we could probably make it work, but it
also could cause problems down the line as the headers change with different OS
versions, and depending on what the changes were, we might end up with silent
breakage.

Personally, I'd be more inclined to just not use importC for zlib, since we
clearly don't need to.

Of course, it would be nice if dmd could just handle the __asm__ stuff
properly, but I guess that that would require that dmd be able to handle
another kind of assembly language.

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