Currently there is no indication of the maximum length of keysym names.
This is statically known, so add the new *internal* following API:
`XKB_KEYSYM_NAME_MAX_SIZE`.
Currently there is no direct way to know the minimum and maximum keysym
values that are assigned, i.e. that have an explicit name or are
Unicode keysyms.
Introduce the new following internal API:
- XKB_KEYSYM_MIN_ASSIGNED
- XKB_KEYSYM_MAX_ASSIGNED
- XKB_KEYSYM_MIN_EXPLICIT
- XKB_KEYSYM_MAX_EXPLICIT
- XKB_KEYSYM_COUNT_EXPLICIT
Also add a bunch of tests to ensure consistant keysyms bounds.
Pierre Le Marre