Windows doesn't do signals much.

util/ack/main.c

@@ -21,7 +21,6 @@ static char rcs_id[] = "$Id$";
 static char rcs_ack[] = RCS_ACK;
 #endif
 
-static int sigs[] = { SIGINT, SIGHUP, SIGTERM, 0 };
 static int arg_count;
 
 static char* srcvar(void);
@@ -85,13 +84,8 @@ int main(int argc, char** argv)
 	if (n_error && !k_flag)
 		exit(n_error);
 
-	for (n_sig = sigs; *n_sig; n_sig++)
-	{
-		if (signal(*n_sig, noodstop) == SIG_IGN)
-		{
-			signal(*n_sig, SIG_IGN);
-		}
-	}
+	if (signal(SIGINT, noodstop) == SIG_IGN)
+		signal(SIGINT, SIG_IGN);
 
 	scanlist(l_first(arguments), elem)
 	{

util/ack/run.c

@@ -179,18 +179,9 @@ static int run_exec(trf* phase, const char* prog)
 
 	if (status)
 	{
-		switch (status & 0177)
-		{
-			case 0:
-				break;
-			case SIGHUP:
-			case SIGINT:
-			case SIGQUIT:
-			case SIGTERM:
-				quit(-5);
-			default:
+		if (status & 0177)
 			error("%s died with signal %d", prog, status & 0177);
-		}
+
 		/* The assumption is that processes voluntarely
 		   dying with a non-zero status already produced
 		   some sort of error message to the outside world.