Image.Colortable doesn't find all colors on IA64.
Imported from http://bugzilla.roxen.com/bugzilla/show_bug.cgi?id=199
Reported by @grubba
Pike v7.1 release 6 running Hilfe v2.0 (Incremental Pike Frontend)
> object img=Image.Image(100,100)->test(99)->scale(400,100);
Result: object
> object c=Image.Colortable(img,256);
Result: object
> img=c*img;
Result: object
> sizeof(c);
Result: 256
> object c2=Image.Colortable(img,256);
Result: object
> sizeof(c2);
Result: 246
> c2*img == img;
Result: 0
This behaviour causes the BMP testsuite to fail on Digital Unix.