GDT and TSS changes (with find fix)
The find fix is that for GNU find (aka linux find), -name only matches the name and -wholename fixes the issue.
For the GDT, the user segments have to be reordered for sysret (even if it is not used I think it's okay to do this) and the TSS is added,
which is important for alternate stacks for interrupts like the page fault or double fault (which could trigger a triple fault without the TSS),
as well as the stacks used when switching to a lower ring.