This allows creating *.checksums files instead of checking against
them when UPDATE_CHECKSUMS is set to True in bootstrap.cfg.
The checksums are also copied to /usr/src so they can be accessed
easily after the bootstrap completes.
- Rename sources to distfiles for clarity.
- Per sys(a/c) distfiles to reduce rootfs.py processing and reduce RAM
usage in sysa.
- Canonicalise early kaem mes/tcc files to kaem script conventions.
- Cleanup unused setup in python.
Dor Askayo
fosslinux
Andrius Štikonas