Windows uses FILETIME, which starts counting from 1st Jan of year 1601 and, unlike time_t, can't be negative, so Windows simply has no way to do timestamp-math for dates before then. SYSTEMTIME (an equivalent of struct tm) can, obviously, represent almost arbitrary date starting from 1st Jan of year 0 (it's unsigned...), but GetDateFormatW() converts it to FILETIME at some point in its implementation, and fails. Unless the whole strftime() implementation of GDate is replaced by something that doesn't rely on WinAPI, this part of the test will never pass.
(cherry picked from commit b009984ea4993deb0047fa873bdd01d97b059ca7)