Turn on HAVE(SYSTEM_FEATURE_FLAGS) on WatchOS and TvOS. This should fix the build after r270542.
<rdar://72146663>
Created attachment 415787 [details] Patch
Created attachment 415790 [details] Patch
Funny that I didn’t spot the missing backslashes.
Committed r270600: <https://trac.webkit.org/changeset/270600> All reviewed patches have been landed. Closing bug and clearing flags on attachment 415790 [details].