Enhance setns syscall decoding

* process.c (sys_setns): New function.
Decode the 2nd syscall argument using clone_flags.
* linux/syscall.h (sys_setns): New prototype.
* linux/dummy.h (sys_setns): Remove.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
diff --git a/process.c b/process.c
index 1325319..4347a87 100644
--- a/process.c
+++ b/process.c
@@ -585,6 +585,17 @@
 }
 
 int
+sys_setns(struct tcb *tcp)
+{
+	if (entering(tcp)) {
+		printfd(tcp, tcp->u_arg[0]);
+		tprints(", ");
+		printflags(clone_flags, tcp->u_arg[1], "CLONE_???");
+	}
+	return 0;
+}
+
+int
 sys_unshare(struct tcb *tcp)
 {
 	if (entering(tcp))