compile.py implements a parser for X11's Compose.pre files. A lot of
code is necessary to interpret character names but thanksfully, the name
of most characters is contained in the file.

The state machine is compiled into two char arrays which unfortunately
requires an expensive initialisation and allocation.

The COMPOSE_PENDING modifier indicate whether a compose sequence is in
progress. The new key of kind Compose_pending sets the current state of
the sequence.

The compose sequences are compiled into a state machine by a python
script into a compact encoding.

The state of the pending compose is determined by the index of a state.