The GCC build has gotten to the point where it's often hard to find the
actual error in the build log. We should look into enabling these
warnings again in the future, but it looks like a lot of them are
bogous.
As time went by, a few files have become mis-formatted w.r.t.
clang-format. This was made worse by the fact that formatting was not
being enforced in extensionless headers. This commit simply brings all
of libcxx/include in-line with clang-format again.
We might have to do this from time to time as we update our clang-format
version, but frankly this is really low effort now that we've formatted
everything once.
