depend-cleanup.sh: Remove everything before the last build epoch.
We were deleting the .a files for llvm when it was build in bootstrap,
but this caused us to rebuild all the bootstrap things since the
bootstrap compiler changed, making the build time 25 minutes instead of
77 seconds on one of my systems. Items before the last rebuild from
scratch epoch are no longer relevant because you have to rebuild
entirely, so the incremental conditions that lead up to them being
needed are no longer true.
Sponsored by: Netflix
Reviewed by: jrtc27, emaste
Differential Revision: https://reviews.freebsd.org/D53693
rm(1): remove whiteouts when forcibly removing directories
Commit 2ed053cde5 changed UFS' VOP_RMDIR() behavior to no longer
ignore whiteouts when determining whether a directory is empty,
unless explicitly requested by the caller. However, this also
necessitates a change to rm(1) to avoid breaking the expected
behavior when forcibly removing directory hierarchies via `rm -fr`.
I neglected to make this follow-on change despite discussing it
in the review for the breaking commit (D45987).
Finally address the breakage by making `rm -fr` imply FTS_WHITEOUT
when rm(1) reads directory contents via fts_read(3). While here,
also fix a logic error which produces a spurious 'No error' warning
message on stdout for each deleted whiteout.
Reported by: csjp
Reviewed by: csjp, kib, olce
Differential Revision: https://reviews.freebsd.org/D53640
(cherry picked from commit 8b92a6ad597e224b616a8b1d6983f3b55c85308e)
