Bug #160591; fixes a buffer underflow.
Reported by B Douglas Hilton <b.d.hilton@verizon.net>

--- tvision/classes/ttermina.cc
+++ tvision/classes/ttermina.cc
@@ -233,7 +233,7 @@
          }
       }
    }
- while (pos-->=queBack);
+ while (pos-->queBack);
 
  return queBack;
 }