Fix some warnings in libwww2

The directory libwww2 now compiles without any warnings with gcc and clang.

libhtmlw/HTML.h

@@ -52,8 +52,8 @@
  * mosaic-x@ncsa.uiuc.edu.                                                  *
  ****************************************************************************/
 
-#ifndef HTML_H
-#define HTML_H
+#ifndef HTMLW_HTML_H
+#define HTMLW_HTML_H
 
 #ifdef MOTIF
 #include <Xm/Xm.h>
@@ -634,5 +634,5 @@ typedef struct _HTMLRec      *HTMLWidget;
 extern WidgetClass htmlWidgetClass;
 
 
-#endif /* HTML_H */
+#endif /* HTMLW_HTML_H */