Do some esoteric Windows magic in lock_and_signal

[catamorphism]

As per a FIXME in the constructor for lock_and_signal in rt/lock_and_signal.cpp.

[catamorphism]

This file no longer exists.

[brson]

It's actually in rt/sync/lock_and_signal.cpp

[catamorphism]

My bad.

[pcwalton]

I'm going to just close this because this is going to be moved into Rust someday.