Integrate libFuzzer with the basesystem

Contact: tech-userlevel@
Mentors: kamil@ + ?
Duration estimate: 3 months

Integrate the LLVM libFuzzer with the basesystem framework.
Build and execute base programs against libFuzzer.

Milestones:

 1. Ensure completeness of the toolchain in the basesystem.
 2. Add a new option for building the basesystem utilities with libFuzzer.
 3. Finish the integration and report bugs.