Use size_t for strlen length temporaries

src/fe-gtk/setup.c

@@ -1364,7 +1364,7 @@ setup_entry_cb (GtkEntry *entry, setting *set)
         int size;
         int pos;
         unsigned char *p = (unsigned char*)gtk_entry_get_text (entry);
-        int len = strlen (p);
+        size_t len = strlen ((const char *) p);
 
         /* need to truncate? */
         if (len >= set->extra)