fix the regression test’s results while here, which have been
broken since cid 10049D9BE5254CE65B8
• get rid of separate copyright file which was intended for De-
bian; track down commits in all files of oksh-mirbsd and mksh
to get correct copyright years per-file, as is BSD custom
of sanitising; since this is supposed to be the lightweight allocator,
with the guarding allocator coming back in later, remove it
reduces memory consumption below what espie's allocator used ☺
similarily simple one from scratch, which however performs
better than espie's with AFREE_DEBUG enabled which took away
the benefit of the double-linked-list approach
all of (core) mksh is now MirOS licenced
