See https://bugs.webkit.org/show_bug.cgi?id=239299#c7, we don't want to warn about unrecognized warnings
This is only a problem for GCC, because Clang has __has_warning() which we use to drop attempts to suppress unrecognized warnings, and I'm pretty sure Clang doesn't warn about unrecognized pragmas anyway. (The IGNORE_WARNINGS macros are only implemented for GCC and Clang.)
https://github.com/WebKit/WebKit/pull/291
Committed r292934 (249699@main): <https://commits.webkit.org/249699@main> Reviewed commits have been landed. Closing PR #291 and removing active labels.
<rdar://problem/91838502>