introduce GENinstanceFree() and GENmodelFree()

To abstract away the business of releasing the memory
  of a struct GENmodel or struct GENinstance.

src/frontend/spiceif.c

@@ -898,7 +898,7 @@ if_setparam_model(CKTcircuit *ckt, char **name, char *val)
                 INPgetMod(ckt, mods->GENmodName, &inpmod, ft_curckt->ci_symtab);
                 if (curMod != nghash_delete(ckt->MODnameHash, curMod->GENmodName))
                     fprintf(stderr, "ERROR, ouch nasal daemons ...\n");
-                FREE(mods);
+                GENmodelFree(mods);
 
                 inpmod->INPmodfast = NULL;
                 break;

src/include/ngspice/gendefs.h

@@ -46,4 +46,9 @@ struct GENmodel {       /* model structure for a resistor */
     IFuid GENmodName;           /* pointer to character string naming this model */
 };
 
+
+void GENinstanceFree(GENinstance *);
+void GENmodelFree(GENmodel *);
+
+
 #endif

src/spicelib/analysis/cktdest.c

@@ -47,12 +47,12 @@ CKTdestroy(CKTcircuit *ckt)
                     GENinstance *next_inst = inst->GENnextInstance;
                     if (DEVices[i]->DEVdelete)
                         DEVices[i]->DEVdelete(inst);
-                    FREE(inst);
+                    GENinstanceFree(inst);
                     inst = next_inst;
                 }
                 if (DEVices[i]->DEVmodDelete)
                     DEVices[i]->DEVmodDelete(model);
-                FREE(model);
+                GENmodelFree(model);
                 model = next_model;
             }
             if (DEVices[i]->DEVdestroy)

src/spicelib/analysis/cktdltm.c

@@ -37,11 +37,11 @@ CKTdltMod(CKTcircuit *ckt, GENmodel *m)
                 fprintf(stderr, "ERROR, ouch nasal daemons ...\n");
 	    error = SPfrontEnd->IFdelUid (ckt, h->GENname,
 		    UID_INSTANCE);
-	    tfree(h);
+	    GENinstanceFree(h);
     }
     if (m != nghash_delete(ckt->MODnameHash, m->GENmodName))
         fprintf(stderr, "ERROR, ouch nasal daemons ...\n");
     error = SPfrontEnd->IFdelUid (ckt, m->GENmodName, UID_MODEL);
-    tfree(m);
+    GENmodelFree(m);
     return(OK);
 }

src/spicelib/analysis/cktmcrt.c

@@ -42,3 +42,17 @@ CKTmodCrt(CKTcircuit *ckt, int type, GENmodel **modfast, IFuid name)
 
     return OK;
 }
+
+
+void
+GENinstanceFree(GENinstance *inst)
+{
+    txfree(inst);
+}
+
+
+void
+GENmodelFree(GENmodel *model)
+{
+    txfree(model);
+}