I got too hasty in landing https://bugs.webkit.org/show_bug.cgi?id=229353, and broke a bunch of tests in the process (I had verified that these tests passed on a previous version of the patch, and did not think that in fixing the watch I would break something else). The root cause appears to be that PlatformUse.h is not a regular header: it gets included in all kinds of places, including files that are not C++ (nor even C!) such as the files defining the sandbox of the network process. And so my including <cstdint> naturally caused massive issues. This patch reverts that particular piece of the previous patch, making USE_LARGE_TYPED_ARRAYS exclusively depend on CPU(ADDRESS64). It is less semantically clean, but seems to be equivalent on all platforms we support (verified with static_asserts in ArrayBuffer.h).
Created attachment 441330 [details] Patch
Comment on attachment 441330 [details] Patch I am reverting https://bugs.webkit.org/show_bug.cgi?id=229353, so this will be merged into the next version of it.
I rolled out the offending patch, and later landed it again with this fix included.