"Undefined identifier FILE" when building Druntime

[Meta via Digitalmars-d-learn]

This happens with a freshly checked out master. I first build 
DMD, which completes successfully. However, when I then try to 
build Druntime, I got the following error messages:

src\core\stdc\wchar_.d(32): Error: undefined identifier FILE
src\core\stdc\wchar_.d(33): Error: undefined identifier FILE
src\core\stdc\wchar_.d(36): Error: undefined identifier FILE
src\core\stdc\wchar_.d(37): Error: undefined identifier FILE
src\core\stdc\wchar_.d(48): Error: undefined identifier FILE
src\core\stdc\wchar_.d(49): Error: undefined identifier FILE
src\core\stdc\wchar_.d(52): Error: undefined identifier FILE
src\core\stdc\wchar_.d(53): Error: undefined identifier FILE
src\core\stdc\wchar_.d(60): Error: undefined identifier FILE
src\core\stdc\wchar_.d(61): Error: undefined identifier FILE
src\core\stdc\wchar_.d(67): Error: undefined identifier FILE
src\core\stdc\wchar_.d(75): Error: undefined identifier FILE
src\core\stdc\stdio.d(551): Error: undefined identifier FILE
src\core\stdc\stdio.d(554): Error: undefined identifier FILE
src\core\stdc\stdio.d(559): Error: undefined identifier FILE
src\core\stdc\stdio.d(562): Error: undefined identifier FILE
src\core\stdc\stdio.d(563): Error: undefined identifier FILE
src\core\stdc\stdio.d(563): Error: undefined identifier FILE
src\core\stdc\stdio.d(565): Error: undefined identifier FILE
src\core\stdc\stdio.d(566): Error: undefined identifier FILE
src\core\stdc\stdio.d(610): Error: undefined identifier FILE