code review 12970043: cmd/gc: &x panics if x does

src/cmd/6l/6.out.h

 // Inferno utils/6c/6.out.h
 // http://code.google.com/p/inferno-os/source/browse/utils/6c/6.out.h
 //
 //      Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
 //      Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
 //      Portions Copyright © 1997-1999 Vita Nuova Limited
 //      Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
 //      Portions Copyright © 2004,2006 Bruce Ellis
 //      Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
 //      Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
@@ skipping 743 matching lines @@
         AAESIMC,
         AAESKEYGENASSIST,
 
         APSHUFD,
         APCLMULQDQ,
 ········
         AUSEFIELD,
         ATYPE,
         AFUNCDATA,
         APCDATA,
+        ACHECKNIL,
 ········
         ALAST
 };
 
 enum
 {
 
         D_AL            = 0,
         D_CL,
         D_DL,
@@ skipping 120 matching lines @@
  * this is the simulated IEEE floating point
  */
 typedef struct  ieee    Ieee;
 struct  ieee
 {
         int32   l;      /* contains ls-man      0xffffffff */
         int32   h;      /* contains sign        0x80000000
                                     exp         0x7ff00000
                                     ms-man      0x000fffff */
 };