Fix this warning:

gfanlib_tropicalhomotopy.h:457:83: warning: operation on 'numberToDrop' may be undefined [-Wsequence-point]
  457 |                         int numberToDrop=(subconfigurationIndex!=0) ? numberToDrop=k+1 : 0;
      |                                                                       ~~~~~~~~~~~~^~~~

--- Singular-Release-4-2-1p3/gfanlib/gfanlib_tropicalhomotopy.h.orig	2021-12-17 11:35:18.000000000 -0700
+++ Singular-Release-4-2-1p3/gfanlib/gfanlib_tropicalhomotopy.h	2022-07-25 10:34:15.834633612 -0600
@@ -454,7 +454,7 @@ template<class mvtyp, class mvtypDouble,
                         //chioices are "relative" so no update is needed.
 
                         choices=parent.choices;
-                        int numberToDrop=(subconfigurationIndex!=0) ? numberToDrop=k+1 : 0;
+                        int numberToDrop=(subconfigurationIndex!=0) ? k+1 : 0;
 
                         choices[subconfigurationIndex-1].first-=numberToDrop;
                         choices[subconfigurationIndex-1].second-=numberToDrop;