dc(1) -e "6 2 / p" is still broken as of r207919

Hello!

Just to remind that still:

~> dc -e "6 2 / p"
Segmentation fault (core dumped)

This was already mentioned on this list:
http://lists.freebsd.org/pipermail/freebsd-current/2010-April/016560.html
and there is a patch proposed in the same thread:
http://lists.freebsd.org/pipermail/freebsd-current/2010-April/016603.html

Note, however, that reverting r203438 also fixes the problem (gabor_at_ CC-ed),
so I'm not sure what is the right way to fix it.
Attached is slightly modified reverse patch to revert 203438.

Thanks,
Alexey.