add sysv ipc message queues (completely untested)

src/ipc/msgctl.c

@@ -0,0 +1,12 @@
+#include <sys/msg.h>
+#include "syscall.h"
+#include "ipc.h"
+
+int msgctl(int q, int cmd, struct msqid_ds *buf)
+{
+#ifdef __NR_msgctl
+	return syscall(SYS_msgctl, q, cmd, buf);
+#else
+	return syscall(SYS_ipc, IPCOP_msgctl, q, cmd, buf);
+#endif
+}