GitLab

The Darwin kqueue implementation doesn't report any event when the
last writer for a fifo is closed.

Fixes #24164

Change-Id: Ic2c47018ef1284bf2e26379f8dd7646edaad4d05
Reviewed-on: https://go-review.googlesource.com/118566

Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>