Ignore all .gclient* files. `gclient sync` seems to now be writing .gclient_previous_custom_vars Bug: None Change-Id: Ie7614bf0b7dc582eb79778f47481139cfcc5f342 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3807760 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Roman Lavrov <romanl@google.com>