warnings cleanup (trunk only)

This covers the warning cleanup bits no one objected to.

include/objclass.h

@@ -111,8 +111,8 @@ struct objclass {
 
 struct class_sym {
 	char sym;
-	char *name;
-	char *explain;
+	const char *name;
+	const char *explain;
 };
 
 struct objdescr {