CTRL-C does not work during script execution

[SuperIlu]

A running script can not be terminated by pressing CTRL-C

This issue is split from #3

[SuperIlu]

Tested this with DOSBox-X and FreeDOS running on VirtualBox.

DOSBox:
neither CTRL-C nor CTRL-BREAK do work

FreeDOS:
Both keys work and the program is terminated.

It seems there is a know issue in DOSBox for CTRL-C/CTRL-BREAK, e.g. see http://www.virtualdub.org/blog/pivot/entry.php?id=338

Nonetheless I will include a function call that should be able to enable/disable the break-keys with the default: "CTRL-C is enabled"

[sinsinpub]

yep, indeed I knew BREAK key not work on DOSBox, that's annoying.
Considering there is even no PAUSE/BREAK key on nowadays keyboard, it's nice to have a alternative hotkey (perhaps something like ctrl+z or ctrl+prtsc) to hook into break interrupt, and ofc be able to opt-in enable/disable.

[SuperIlu]

I'll give it a thought. jSH scripts (in contrast to DOjS scripts with the Loop() function) have no "forced" break point where the JS runtime could regularly check for such a key.
But maybe I'm able to come up with something...

[SuperIlu]

I did check with the author of DOSBox-X and this is the result:

• MS-DOS and FreeDOS do support it, but only if the program reads/writes from/to the console
• DOSBox-X does support it, but only if the program does reads from the console (this will be fixed to behave like MS-DOS/FreeDOS)
• plain DOSBox does not support CTRL-C/CTRL-BREAK at all

There will be a new function CtrlBreak() which enables/disables CTRL-C/CTRL-BREAK handling

[SuperIlu]

fixed/documented in V0.8

[SuperIlu]

Fixed in DOSBox-X: joncampbell123/dosbox-x#2525