uses find(1) in a non-POSIX way. The trouble is that -maxdepth is
not an option for POSIX find(1). His NetBSD 1.6.2 system tripped
over that. I converted the -maxdepth uses to -prune, which is
POSIX-compatible.
While I was in makeplist, I wrote a comment about the xargs/find/read
cleverness that I use to generate the @dirrm directives.
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