Some tests calling spot.automaton('non-existing|') where failing either
with a "process returned 127", or, under heavier load, with "failed to
read from...". The latter occur if we poll() the exit status before the
children has had the tame to finish.
* wrap/python/spot.py: Make sure we wait for the child process if we
reach EOF, so that we can report the error status.
* wrap/python/tests/automata-io.ipynb, wrap/python/tests/piperead.ipynb:
Update.
* src/hoaparse/hoaparse.yy, src/hoaparse/hoascan.ll,
src/hoaparse/parsedecl.hh, src/hoaparse/public.hh:
Add a way to read automata from a file descriptor.
* wrap/python/spot.py: Add machinery to read from
pipes.
* wrap/python/tests/piperead.ipynb: New file.
* wrap/python/tests/Makefile.am: Add it.
* wrap/python/tests/run.in: Setup PATH.
