small cleanup switched DTD validation to use only regexp when configured

* HTMLparser.c: small cleanup
* valid.c xmlregexp.c: switched DTD validation to use only regexp
  when configured with them. A bit of debugging around the determinism
  checks is still needed
Daniel

xmlregexp.c

@@ -161,6 +161,7 @@ struct _xmlRegAtom {
     int max;
 
     void *valuep;
+    void *valuep2;
     int neg;
     int codepoint;
     xmlRegStatePtr start;