Build error after PR #3665

[fwsGonzo]

PR #3665 introduces a build error for me. I recently saw the release 1.5.7 improved performance and I wanted to check this out. Updating my submodule resulted in the error:

/usr/bin/ccache ... -O3 -o ext/zstd/build/cmake/lib/CMakeFiles/libzstd_static.dir/__/__/__/lib/decompress/huf_decompress_amd64.S.o -c ext/zstd/lib/decompress/huf_decompress_amd64.S
/usr/bin/ccache: invalid option -- 'D'

I bisected it to the aforementioned PR 3665.

The zstd project builds again by removing the if statement introduced in the PR. I don't have Xcode so I can't make a change that solves my Ubuntu ccache build issue as well as building on Xcode.

[Cyan4973]

It would be great to have a test in CI able to reproduce this issue.
I've been trying to reproduce it on 2 different systems so far, and been unable to witness the same issue.
It seems tied to a specific way to compile the source code, more specifically the assembly source file.