build-toolchain failing on OS X 10.12

Hi all,

I am getting errors compiling the toolchain from the tip of master.
Specifically inside of stdlib/SDK/Foundation, it has some syntax issue
which leads to compilation failure.
I did a swift/utils/update-checkout then swift/utils/build-toolchain.
I see the CI builds are green, am I out of sync some where? Any help would
be much appreciated.

Thanks

Dave