code review 6185047: runtime: fix c compiler warning

src/pkg/runtime/vlrt_arm.c

 // Inferno's libkern/vlrt-arm.c
 // http://code.google.com/p/inferno-os/source/browse/libkern/vlrt-arm.c
 //
 //         Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
 //         Revisions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com).  All rights reserved.
 //         Portions Copyright 2009 The Go Authors. All rights reserved.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
 // in the Software without restriction, including without limitation the rights
@@ skipping 179 matching lines @@
 float
 _v2f(Vlong x)
 {
         return _v2d(x);
 }
 
 void
 runtime·int64tofloat64(Vlong y, double d)
 {
         d = _v2d(y);
+        USED(&d); // FLUSH
 }
 
 void
 runtime·uint64tofloat64(Vlong y, double d)
 {
         d = _ul2d(y.hi)*4294967296. + _ul2d(y.lo);
+        USED(&d); // FLUSH
 }
 
 static void
 dodiv(Vlong num, Vlong den, Vlong *q, Vlong *r)
 {
         ulong numlo, numhi, denhi, denlo, quohi, quolo, t;
         int i;
 
         numhi = num.hi;
         numlo = num.lo;
@@ skipping 591 matching lines @@
         return lv.hi > rv.hi ||
                 (lv.hi == rv.hi && lv.lo > rv.lo);
 }
 
 int
 _hsv(Vlong lv, Vlong rv)
 {
         return lv.hi > rv.hi ||
                 (lv.hi == rv.hi && lv.lo >= rv.lo);
 }