Reformat code

[unbrice]

The code uses the GNU style, which few projects use and looks unfamiliar to anyone else. A pass through clang-format or indent should take care of that.

[unbrice]

@kakra Do you want to do it? Otherwise I am happy to do it myself (after merging what's in the pipeline) but worried I may conflict with some of your ongoing patch.

[kakra]

I'll have a look and rebase my patches if it works.