Workaround for rust-lang-deprecated/time#137.
Workaround for rust-lang-deprecated/time#137.

In Windows libtime populate `time::Tm` from `SYSTEMTIME`, which
unfortunately does not contain `tm_yday`. It tries to calculate it
from other fields, but... as one can say it is completely wrong.
Since other fields are copied in verbatim we work around this
problem by using a less efficient method.

Fixes #85.

lifthrasiir/rust-chrono,tshakah/rust-chrono