Symlink detection broken in Stdio.Stat

Imported from http://bugzilla.roxen.com/bugzilla/show_bug.cgi?id=2815

Reported by Martin Nilsson, IDA nilsson@pike.ida.liu.se

bash-2.03$ cd Pike/7.3/src/
bash-2.03$ ls -la Pike.pmod
lrwxrwxrwx   1 nilsson  nilsson       56 Nov  1 20:33 Pike.pmod ->
/home/nilsson/Pike/7.3/lib/modules/Parser.pmod/Pike.pmod
bash-2.03$ pike
Pike v7.3 release 14 running Hilfe v3.1 (Incremental Pike Frontend)
> object x=file_stat("Pike.pmod");
> x->mode;
Result 1: 33204
> x->islnk;
Result 2: 0