include, kernel: minor fixes to make compiling and linking work with clang.

(fixing warnings)

kernel/system/do_privctl.c

@@ -98,7 +98,7 @@ PUBLIC int do_privctl(struct proc * caller, message * m_ptr)
 	for (i=0; i< NR_SYS_CHUNKS; i++)		/* remove pending: */
 	      priv(rp)->s_notify_pending.chunk[i] = 0;	/* - notifications */
 	priv(rp)->s_int_pending = 0;			/* - interrupts */
-	sigemptyset(&priv(rp)->s_sig_pending);		/* - signals */
+	(void) sigemptyset(&priv(rp)->s_sig_pending);	/* - signals */
 	reset_timer(&priv(rp)->s_alarm_timer);		/* - alarm */
 	priv(rp)->s_asyntab= -1;			/* - asynsends */
 	priv(rp)->s_asynsize= 0;