[PATCH] ntdll: Fix race condition with fd_cache when duplicating handle.

[Daniel Lehman]

> > do you mean if the current process received a file handle from another
> > process and wanted to close the handle on the remote end?
>
> Yes, that's why there's a source process parameter.

yeah, my fix doesn't cover receiving a file handle (or sending on
behalf of another process).  there isn't an existing way (that i see)
to tell the other process to remove the cached fd

i was hoping to at least fix the race in this case where the current
process is sending

thanks
daniel