This helper acts like /dev/zero (outputs \x00 indefinitely) in an
OS-independent fashion. This ensures we don't need to special-case
around Windows in tests that want to open /dev/zero.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
(cherry picked from commit 2f8d3e1c33f77187c68893803018756d43daff15)
Signed-off-by: Andrew Hsu <andrewhsu@docker.com>
4cd44b4bf2