- This PR also adds a DEBUG cmake option that enables -DTOX_DEBUG.
- We also remove `-Wall`, because there are too many warnings, and nobody really
looks at them at the moment. We'll see about fixing them soon. We'll also want
to enable `-Werror` at some point.
- Finally, this PR enables `-O3` to make sure toxcore still works correctly
under heavy compiler optimisations.
This is in preparation for having multiple types of build. One of the future
builds will be a hstox build, another may be frama-c or some other static
analyser. It makes sense to split these up into multiple builds, because each of
them can take a while, and running them in parallel will speed things up. Also,
the hstox test coverage should be reported separately from the toxcore auto_test
coverage.
