-f[no-]var-tracking-assignments is GCC-only
Created attachment 366954 [details] Patch
This was introduced in bug 185462 and causes JSCOnly to fail on Mac. (Interestingly, "unknown argument" is just a warning for clang-cl, but it's an error for clang proper.)
I guess you can just remove it because it's broken, bug #186273. The warning seems to be gone in GCC 9 anyway.
Please close that bug if you take this approach.
Oh sure, happy to remove it instead if we no longer need it.
Created attachment 366973 [details] Patch for landing
Comment on attachment 366973 [details] Patch for landing Clearing flags on attachment: 366973 Committed r244044: <https://trac.webkit.org/changeset/244044>
All reviewed patches have been landed. Closing bug.
<rdar://problem/49710076>