This prevents building internally for arm64. libwebrtc is the only project which sets VALID_ARCHS = $(ARCHS_STANDARD_64_BIT), which appears to be the culprit.
<rdar://problem/102397752>
Pull request: https://github.com/WebKit/WebKit/pull/7227
Committed 257540@main (3c4cf6cf5719): <https://commits.webkit.org/257540@main> Reviewed commits have been landed. Closing PR #7227 and removing active labels.