Fixes: ccb4124a4172b ("Fix -gz=zlib options for linker")
I think "Fixes:" is not appropriate because that patch only intended to change the behavior on Gnu.cpp.
I think see the rationale for -gz=zlib affecting linking: clang -gz=zlib a.o b.o will provide --compress-debug-sections=zlib.
However, for clang -gz=zlib a.c b.c, -gz=zlib affecting assembly may be unnecessary: the object files are compressed just to be uncompressed immediately by the linker.
I can drop the Fixes trailer (I added it as we've adopted it in FreeBSD from Linux). That said, the referenced patch changed Gnu, AMDGPU, and HIP. My main goal here is to get the final library / executable artifacts to have compressed debug, we can look more at the intermediate bits later.
As an aside I'd like to see how we can prevent this kind of divergence; I would expect (what is currently) FreeBSD to be approximately equal to Gnu.
When we see an issue on Linux, it is hard to know whether it also happens to FreeBSD because we do not use FreeBSD on a daily basis. I think a reasonable solution is to add you as reviewer when we encounter similar issues on Linux in the future.