Try dynamically heap allocating 'ex' instead of a stack-allocated VLA…

… to avoid ASan stack-overflow

src/topmodel.c

@@ -143,13 +143,13 @@ extern void topmod(FILE *output_fptr, int nstep, int num_topodex_values,
   current_time_step, *sump, *sumae, *sumq, stand_alone
   added as function input parameters */
 
-double ex[num_topodex_values+1]; //+1 to maintin 1 based array indexing
 //NJF TODO consider warning on all program limits here since this is essentially
 //"the model" where those assumptions may not be valid...
 if(num_topodex_values > WARN_TOPODEX_INCREMENTS){
   printf("WARNING: num_topodex_values, %d, is greater than %d\n",
          num_topodex_values, WARN_TOPODEX_INCREMENTS);
 }
+double *ex = malloc(sizeof(double)*(num_topodex_values+1)); //+1 to maintin 1 based array indexing
 int ia,ib,in,irof,it,ir;
 double rex,cumf,max_contrib_area,ea,rint,acm,df;
 double acf,uz,sae,of;
@@ -364,6 +364,8 @@ for(ia=1;ia<=num_topodex_values;ia++)
 
   }
 
+free(ex);
+
 return;
 
 }