Patch for MiniSat+ to also output mapping from OPB to CNF variables when using -cnf option

cnf_mapping.diff

--- PbSolver.C.orig     2025-07-09 22:25:44.393796385 +0200
+++ PbSolver.C  2025-07-09 22:24:07.817685378 +0200
@@ -535,10 +535,22 @@
         addConstr(goal_ps, goal_Cs, opt_goal, -1),
         convertPbs(false);

-    if (opt_cnf != NULL)
-        reportf("Exporting CNF to: \b%s\b\n", opt_cnf),
-        sat_solver.exportCnf(opt_cnf),
+    if (opt_cnf != NULL) {
+        reportf("Exporting CNF to: \b%s\b\n", opt_cnf);
+        sat_solver.exportCnf(opt_cnf);
+        reportf("Exporting OPB to CNF mapping to %s.map\n", opt_cnf);
+        char fnbuf[4096];
+        snprintf(fnbuf, sizeof(fnbuf), "%s.map", opt_cnf);
+        FILE *f = fopen(fnbuf, "wt");
+        if(f) {
+            size_t n = index2name.size();
+            for (size_t i = 0; i<n; i+=1) {
+                fprintf(f, "%s\n", index2name[i]);
+            }
+            fclose(f);
+        }
         exit(0);
+    }

     bool    sat = false;
     int     n_solutions = 0;    // (only for AllSolutions mode)