inp2q.c, #16/23, emit a message and give up, if we couldn't find the modelname token

Thats a functional change of ngspice.

So far we did cook up a "default" model when we didn't find a model token.
But this was buggy anyway, because in such cases we silently dropped
  a token from beeing processed by PARSECALL()
Now, we emit a message, and skip this line alltogether.

src/spicelib/parser/inp2q.c

@@ -69,6 +69,8 @@ void INP2Q(CKTcircuit *ckt, INPtables * tab, card * current, CKTnode *gnode)
         INPtermInsert(ckt, &nname[i], tab, &node[i]);
     }
 
+    model = NULL;
+
     i = 3;
     INPgetTok(&line, &nname[i], 1);
 
@@ -91,13 +93,20 @@ void INP2Q(CKTcircuit *ckt, INPtables * tab, card * current, CKTnode *gnode)
            INPtermInsert(ckt, &nname[i], tab, &node[i]);
            i = 5;
            INPgetTok(&line, &nname[i], 1);
-           model = nname[i];
-           INPinsert(&model, tab);
-           current->error = INPgetMod(ckt, model, &thismodel, tab);
+           if (INPlookMod(nname[i])) {
+               model = nname[i];
+               INPinsert(&model, tab);
+               current->error = INPgetMod(ckt, model, &thismodel, tab);
+           }
 #endif
         }
     }
 
+    if (!model) {
+        LITERR ("could not find a valid modelname");
+        return;
+    }
+
     if (i == 3) {
         /* 3-terminal device - substrate to ground */
         node[3] = gnode;