Add preference setting for interrupt command

[David Aspinall]

This is prover specific and (in the case of Isabelle), unfortunately hard to determine. Code currently has "killall -2 HOL" hardwired. This should be moved to a prover preference setting (near Use PGIP interrupts)

[David Aspinall]

A message from Makarius on the Isabelle mailing list suggests a way through here. Ideally it would be better *not* to have a per-prover setting.

Peeking at comint.el reveals that emacs signals the whole process group of 
the controlling pty here.  I've managed to imitate this behaviour in the 
shell using kill with negated PID like this:

  kill -INT -- -4711

Also note that the Isabelle/Isar toplevel ignores any INT signals unless 
it actually runs a command.  To test kills more easily you may use the raw 
ML toplevel, which reports something like ``Compilation interrupted''.

[David Aspinall]

Fixed by adding preference for interrupt OS command after all. Seems to be no way to signal sub-processes in Java. Best solution may be to add wrappers to provers to intercept <interruptprover> command.

[David Aspinall]

mylyn/context/zip

[David Aspinall]

Milestone PG-Eclipse-1.0.6 deleted