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I probably have to try this very lightweight package manager (~500MB for a ~4kiB
dependency seems very reasonable...).

This ends the PoC phase, every part has a basic and working implementation!
Now it is possible to focus on security, challenge and testcase editing and
website interface! :)

Many parts are either incomplete or dangerous (or both).
It is designed with many hard-coded items, but it seems better to tackle this
problem with a first working solution and successive improvements...

Currently, the testcase system support registers and memory initialization.
Building system is able to assemble and link an init file, testcase-generated
source and submission sources.
Error reporting is satisfying for a first version.

Large improvements to perform:
- allow testcases to be handle by the database (at least using weird toml config
for instance, if DB tables seems overkill)
- allow build skeleton to be defined from the database
- secure the build process, or at least specify the minimal API for plugin a
secure builder?

Isn't that weird enough to worry?