- Do not require any libraries installed, download everything
from upstream git, statically compile (use include, libs and pkg-config
from local directory under tests/fuzz).
Script should work both from OSS-Fuzz and locally.
- Do not require local protobuf (only staticallly compiled, see above).
- Add README.md (TBD, still not finished).
- Fix make dist and distcheck.
- Remove common.[ch] as we can use internal function.
This makes fuzzers also C++ only (remove CFLAGS from Makefile).
