xkbcomp contains a bug detected by gcc:

compat.c:249: warning: comparison is always false due to limited range of data type


static Bool
AddGroupCompat(CompatInfo *info,unsigned group,GroupCompatInfo *newGC)
{
GroupCompatInfo *       gc;
unsigned                merge;

    merge= newGC->merge;
    gc= &info->groupCompat[group];
    if ((newGC->fileID<0)||       /* This is line 249 */
        ((gc->real_mods==newGC->real_mods)&&(gc->vmods==newGC->vmods))) {
        return True;
    }
    if (((gc->fileID==newGC->fileID)&&(warningLevel>0))||(warningLevel>9)) {
        WARN1("Compat map for group %d redefined\n",group+1);
        ACTION1("Using %s definition\n",(merge==MergeAugment?"old":"new"));
    }
    if (merge!=MergeAugment)
        *gc= *newGC;
    return True;
}

The "if ((newGC->fileID<0)" test is always false because the fileID member
of the GroupCompatInfo struct is an unsigned char, so it can never be less
than zero.