Patch: ucdata 2.4 bugs (ITS#1751)

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Written by Hallvard B. Furuseth and placed into the public domain.
This software is not subject to any license of the University of Oslo.
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ucgendat.c accessed unallocated memory when i == ncodes_size.

The changes others are trivial, I just include them since I'm patching
ucdata anyway:

ucdata.c   had some pointless '0 <= unsigned' comparisons.

ucstr.c    assigned a long* to an unsigned long*.  Since malloc()
           returns void*, the result need not be cast at all.

I'll send the ucgendat.c and ucdata.c patches to Mark Leisher
<mleisher@crl.nmsu.edu>.

Hallvard B. Furuseth <h.b.furuseth@usit.uio.no>, April 2002.