Build error after PR #3665

PR https://github.com/facebook/zstd/pull/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.