findsubname(), fix lvalues

src/frontend/numparam/spicenum.c

@@ -190,10 +190,10 @@ findsubname(dico_t *dico, SPICE_DSTRINGPTR dstr_p)
             entry_t *entry;
             /* check for known subckt name */
             spice_dstring_reinit(&name);
-            int (t - s) = (int) (p - s - 1) + 1;
+            char *t = s + (int) (p - s - 1) + 1;
             while (alfanum(s[(t - s)])) {
                 cadd(&name, toupper_c(s[(t - s)]));
-                (t - s)++;
+                t++;
             }
             entry = entrynb(dico, spice_dstring_value(&name));
             if (entry && (entry->tp == NUPA_SUBCKT)) {