pac: collect exogenous variables in growth argument to pass exo use test in ModFile.cc

src/ComputingTasks.cc

@@ -279,6 +279,13 @@ PacModelStatement::PacModelStatement(string name_arg,
 {
 }
 
+void
+PacModelStatement::checkPass(ModFileStructure &mod_file_struct, WarningConsolidation &warnings)
+{
+  if (growth)
+    growth->collectVariables(SymbolType::exogenous, mod_file_struct.pac_params);
+}
+
 void
 PacModelStatement::overwriteGrowth(expr_t new_growth)
 {

src/ComputingTasks.hh

@@ -152,6 +152,7 @@ public:
                     double steady_state_growth_rate_number_arg,
                     int steady_state_growth_rate_symb_id_arg,
                     const SymbolTable &symbol_table_arg);
+  void checkPass(ModFileStructure &mod_file_struct, WarningConsolidation &warnings) override;
   void overwriteGrowth(expr_t new_growth);
   void writeOutput(ostream &output, const string &basename, bool minimal_workspace) const override;
   void writeJsonOutput(ostream &output) const override;