JSC LLint extractors fail to compile when WTF headers in build directory are stale
<rdar://problem/100315062>
Pull request: https://github.com/WebKit/WebKit/pull/4623
Committed 254820@main (fe4695d7e04b): <https://commits.webkit.org/254820@main> Reviewed commits have been landed. Closing PR #4623 and removing active labels.