BUG: Need to use #cmakedefine for HAVE_UNICODE_WCHAR.

Utilities/cmxmlrpc/xmlrpc_config.h.in

@@ -26,7 +26,7 @@
 
 #define ATTR_UNUSED @ATTR_UNUSED@
 
-#define HAVE_UNICODE_WCHAR @HAVE_UNICODE_WCHAR@
+#cmakedefine HAVE_UNICODE_WCHAR @HAVE_UNICODE_WCHAR@
 
 #define DIRECTORY_SEPARATOR "@DIRECTORY_SEPARATOR@"