Put a comment here about using suser() to determine super-user-ness.

Using suser() means that the p_acflag will (can) be set, to show that
a process used super-powers during execution.  It also makes it easier
to restrict roots we don't trust later on.

Reviewed by:	bde

sys/sys/ucred.h

@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ucred.h	8.4 (Berkeley) 1/9/95
- * $Id$
+ * $Id: ucred.h,v 1.8 1997/02/22 09:46:19 peter Exp $
  */
 
 #ifndef _SYS_UCRED_H_
@@ -39,6 +39,9 @@
 
 /*
  * Credentials.
+ *
+ * Please do not inspect cr_uid directly to determine superuserness.
+ * only the suser() function should be used for this.
  */
 struct ucred {
 	u_short	cr_ref;			/* reference count */