Add custom handling for SIGINT (i.e. Ctrl C)

This should allow windows users to Ctrl-C just like their
*nix bretheren have been able to do forever.

kotter/src/main/kotlin/com/varabyte/kotter/terminal/system/SystemTerminal.kt

@@ -5,11 +5,13 @@ import kotlinx.coroutines.currentCoroutineContext
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.isActive
+import org.jline.terminal.Terminal.Signal
 import org.jline.terminal.TerminalBuilder
 import org.jline.utils.InfoCmp
 import java.io.IOException
 import java.io.OutputStream
 import java.io.PrintStream
+import kotlin.system.exitProcess
 
 /**
  * A [Terminal] implementation which interacts directly with the underlying system terminal.
@@ -31,6 +33,10 @@ class SystemTerminal : Terminal {
  // Swallow keypresses - instead, we will handle them
  enterRawMode()
 
+ // Handle Ctrl-C ourselves, because Windows otherwise swallows it
+ // See also: https://github.com/jline/jline3/issues/822
+ handle(Signal.INT) { exitProcess(130) } // 130 == 128+2, where 2 == SIGINT
+
  val disabledPrintStream = PrintStream(object : OutputStream() {
  override fun write(b: Int) = Unit
  })