update cpplint configuration

[dirk-thomas]

The patch also implements a custom include guard pattern which follows the Google style guide with only one difference: instead of a single separator between folder names / namespaces and filenames it uses two. This ensures that separate packages have unique include guards.

The following example would otherwise in the same colliding include guards:

• package foo_bar has a file baz.hpp
• package foo has a file bar_baz.hpp

ament/ament_index#6 is an example what we need to update to make our code compliant with cpplint.

[wjwwood]

lgtm

[dirk-thomas]

@esteve @jacquelinekay @tfoote Do you all agree to follow this style?

If yes, I will update the style guide in the wiki accordingly and we can start updating existing code to pass this linter before enabling it globally.

[jacquelinekay]

Alright, I pledge to follow the Google C++ style guidelines again.

Migrating the codebase back to this style will be an interesting process. Do we plan on doing it gradually or in one pass?

[wjwwood]

It shouldn't be too different from our current style. These addendums to the google style guide should be mentioned in our development guide: https://github.com/ros2/ros2/wiki/Developer-Guide#c-1 (which I believe Brain has gone through and made up to date recently, but if it needs more changes then they should be made since it's linked from our main ros2 wiki).

[tfoote]

+1 to doing a double underscore between package name and file path.

It would be good to do a focused effort to get it migrated so we can turn on the automated checking soon.