buck-out directory as cachedir

[izissise]

Hello,

When building with Buck2, a buck-out directory is created. Users typically do not want this directory to be backed up. Many backup tools ignore directories that contain a file named CACHEDIR.TAG with the following content:

Signature: 8a477f597d28d172789f06886806bc55
# This file is a cache directory tag created by Buck2.
# For information about cache directory tags, see:
#    http://www.brynosaurus.com/cachedir/

More information can be found here: https://bford.info/cachedir/

It would be great if Buck2 could automatically add this file immediately after creating the buck-out directory.

Thanks,
Hugues

[izissise]

I'm willing to add this, but I'm not sure where to start, it seems it would have its place in buck-prelude?