I have extensive experience working with ksh93 and porting it
between architectures. I volunteer to be maintainer.
Be careful what you wish for :).
As mentioned in the Makefile, its broken on sparc64. I also noticed a
number of tests having some problems on 4.x/alpha (haven't tried 5.x/alpha).
arith.sh was one (may need -mieee) and functions.sh was another (went and
ate CPU time and never came back).