After banging my head against this for two evenings I decided I have to
drop it and find someone else with better skills at this level or experience
with debuging the culprit...

Pkgsrc switched to perl 5.8.x as the default perl. This is fine, but 
unfortunately on sparc64 this perl fails lots of it's self tests - while the
5.6.x one did manage to succeed nearly all of them (some are destined to
lose in a pkgsrc environment).

This starts with very basic things like

  print int(4.7);

printing "5" instead of "4". More failure in the "pack" tests etc. and ends
in an endless loop somewhere in the bignum stuff. Or maybe I'm just not
patient enough.

I found little to no help on the perl web pages or mailing archives, and
they won't even let you look at bug reports without registering first - 
anyway, if someone has been inside (modern) perl before and could give me
some hints, or even likes to debug this himself - that would be extremely
helpfull.

Martin