p_stat() should follow symlinks on windows

p_stat() should follow symlinks on win32, like its Unix counterpart.

Unfortunately, I am not adding a unit test.  I have puzzled over this one for a while.  Only administrators can make links on Windows.  I'm not sure how to detect when you've run clar as an administrator.  We can't even say "hey, let's not run the unit tests if I couldn't make a link" because it appears that `CreateSymbolicLink()` returns 0 *even when it didn't do anything because you're not an Administrator*...  And after all that this test would only ever work when you ran the test suite as administrator.  Sigh.