This is particularly important for src/tests/satmin.test, where ltl2tgba
might be killed while writing a huge temporary file used for SAT-based
minimization.  Before this patch, the temporary files would remain in
src/tests/satmin.dir/, easily overflowing the 100GB limit of the docker
containers we use on the build farm.

* src/bin/common_setup.cc: Catch termination signals for all tools,
even those that do not yet clear temporary files.
* configure.ac: Check for sigaction.