Fix decoding of pid_t arguments of kill and tgkill syscalls

* signal.c (SYS_FUNC(kill), SYS_FUNC(tgkill)): Print pid_t syscall
arguments using %d format.
diff --git a/signal.c b/signal.c
index ad1d967..f089050 100644
--- a/signal.c
+++ b/signal.c
@@ -451,8 +451,8 @@
 
 SYS_FUNC(kill)
 {
-	tprintf("%ld, %s",
-		widen_to_long(tcp->u_arg[0]),
+	tprintf("%d, %s",
+		(int) tcp->u_arg[0],
 		signame(tcp->u_arg[1]));
 
 	return RVAL_DECODED;
@@ -460,9 +460,9 @@
 
 SYS_FUNC(tgkill)
 {
-	tprintf("%ld, %ld, %s",
-		widen_to_long(tcp->u_arg[0]),
-		widen_to_long(tcp->u_arg[1]),
+	tprintf("%d, %d, %s",
+		(int) tcp->u_arg[0],
+		(int) tcp->u_arg[1],
 		signame(tcp->u_arg[2]));
 
 	return RVAL_DECODED;