added support for large file, tested with a 3+GB instance, and some

* libxml.h include/libxml/parser.h parser.c xmlIO.c DOCBparser.c:
  added support for large file, tested with a 3+GB instance,
  and some cleanup.
* catalog.c: added a TODO
* Makefile.am: added some "make tests" comments
Daniel
diff --git a/libxml.h b/libxml.h
index 6b7476f..8b1b949 100644
--- a/libxml.h
+++ b/libxml.h
@@ -9,6 +9,15 @@
 #ifndef __XML_LIBXML_H__
 #define __XML_LIBXML_H__
 
+#ifndef NO_LARGEFILE_SOURCE
+#ifndef _LARGEFILE_SOURCE
+#define _LARGEFILE_SOURCE
+#endif
+#ifndef _FILE_OFFSET_BITS
+#define _FILE_OFFSET_BITS 64
+#endif
+#endif
+
 #if defined(WIN32) && !defined(__CYGWIN__)
 #include "win32config.h"
 #elif defined(macintosh)