- Build option `build_docs` was renamed to `with_docs` quite sometime ago:
3f2a6718df.
This means that the manpage were not being build.
- Remove CFLAG `-fno-strict-aliasing` seems to not be used anywhere in the
upstream repository. This was probably added for `compton` a long time
ago and never removed, since I can't find the commit that added this.
- Use release build. This is recommended upstream:
https://github.com/yshui/picom#to-build.
