When WITH_REPRODUCIBLE_BUILD is on, use mtree to pin the file times to PKG_TIMESTAMP.
mtree lists files in lexicographical order, removing the non-determinism from `tar -cf .`
PR: 283214
---
**status:** in development
**notes**
`make -j $(sysctl -n hw.cpu) packagesystem` is currently non-deterministic for base.txz
**dev work**
TODO:
- DONE verify schg
- DONE do not apply file time when WITHOUT_REPRODUCIBLE_BUILD
- DONE apply for all dist files when run as root
- document
TRY:
- fix -j non-determinism
DEFER:
- consolidate NO_ROOT