Crash with empty dictionary

I'm fooling around with tsearch, and bumped into a segfault, when using
a custom ispell dictionary with DictFile pointing to an empty file.
NISortDictionary assumes there's at least one word in the dictionary,
and crashes on line 941:

> Conf->AffixData[1] = pstrdup(Conf->Spell[0]->p.flag);

I'm not sure if this is a sane way to set up a dictionary, but surely
seg faulting is not the right thing to do. Should we throw an error on
an empty dict file, or should we swallow it without crashing?

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com