Convert all source files to a unified coding style using clang-format

[augustofg]

The code style is not consistently used, and the lack of proper indentation makes navigation and modification hard and error-prone. I propose using clang-format to convert all source files to an common style, and enforce the new style in the CI.

There are some predefined styles we can choose from (LLVM, GNU, Google, Chromium, Microsoft, Mozilla, WebKit) or it is possible to create a custom .clang-format file.

I can volunteer to implement this proposal if there is enough interest.

[rfuest]

The main GTKWave code should already use a consistent coding style and there is also a clang-format configuration file in the repository: https://github.com/gtkwave/gtkwave/blob/master/.clang-format

Which part of the codebase are you referring to?

... and enforce the new style in the CI.

Maybe as a warning, but in my experience the output of clang-format isn't super consistent between versions and I wouldn't want CI to become flaky because of this.

[augustofg]

Sorry, I was looking at an older version of gtkwave, didn't noticed that it was already reformated. As for running clang-format in the CI, a warning would be enough in my opinion.