[isabelle-dev] /bin/kill broken on some recent Linux versions

[Makarius]

Hard to believe that such elemenary things could be broken, but we have a 
general convergence of low quality of *all* operating systems.

The workaround is in Isabelle/3610ae73cfdb.

If anybody stumbles over Isabelle/Scala of a different version failing to 
terminate external processes, that tiny change could be applied on the 
spot.  JVM-based timeout is affected as well, as it requires kill -INT.


 	Makarius