Can't compile Phobos git master

[Andrej Mitrovic]

I'm getting compile errors from commit
2899a9481b7ef59bfc5c55ed06876c72f0ede4bd onwards.
log:
    Sat Sep 24 22:01:44 2011 -0700
    Merge pull request #257 from jmdavis/datetime
    Fixed DST issues in std.datetime.

I'm getting this via `make -f win32.mak`:

std\datetime.d(30196): Error: undefined identifier REG_TZI_FORMAT

I don't understand how the autotester is green all this time?