bad segfault when hitting control-c

[was]

Try this:

sage: n=factor(2^997-1)
[hit control c]
---------------------------------------------------------------------------
<type 'exceptions.KeyboardInterrupt'>     Traceback (most recent call last)

sage: gp.eval('factor(2^997-1)')
[hit control c]
Segmentation fault (core dumped)

... Do the same with Magma:

sage: magma.eval('Factorization(2^997-1)')
Segmentation fault (core dumped)

[was]

This is now fixed for the next SAGE release by Stein and Tornaria. The fixes involved fixing some mistakes in gen.pyx a rewriting interrupt.c/h somewhat.