release_notes_3111

Release Notes

QEMU: Prefer host pkg-static more often for speed.
jail -d: If stdin is a TTY, confirm before proceeding.
jail -c: Always copy in QEMU emulator, even if not building from src.
Support ports_env.sh from Ports r399170 and r399171. This speeds up dependency calculations.
Null-mount read-only /rescue and /nxb-bin into the jails as they will not change.
Add a MUTABLE_BASE option (default yes) to experiment with null-mounting of base
jail: Prefer https://download.FreeBSD.org for snapshot downloads from FreeBSD.
Optimize jail startup/cloning/rollback and mtree comparisons.
Fix some hard-coded temporary files (sandboxed in jails).
Kill processes before remounting/rolling back the builder FS, rather than after.
jail -c: Fix checking MANIFEST checksums.
jail -c: Support pre-distributed MANIFESTs for checksum comparing.
QEMU: Remove duplicate NM from make.nxb.conf.
Fix installation instruction on the Readme