xkbcomp: Drop the key name LUT after compilation Since it is not usual to lookup for keys by their names, we can drop it to save allocations (about 2KiB on usual keymaps). We use an union of the LUT with the aliases array and try to reuse the memory allocated by the LUT. We only do so if the space is trivially available: either before the first alias entry or after the last entry, which is possible in practice, so that we get the best performance. Else we allocate a new array.