While working on the first pull request to use c++17 in rclcpp (ros2/rclcpp#1598) I found that turning on c++17 on Windows (using MSVC) produced many, many warnings.

In order to make progress on that pull request I disabled the warnings as the warnings themselves suggested with this commit:

ros2/rclcpp@ac4b35c

I think we should triage them, at the very least, between the Galactic API freeze and the Galactic release, so I'll add this (for now) to the Galactic project.