64bit Integers for large files (Expat 2.0)

This has been proposed recently. As I am not a cross-platform expert,
I suggest a simple solution:

A new conditional define:

#ifdef XML_LARGE_SIZE  /* Use large integers for counts and positions. */
typedef long long XML_Index;
typedef unsigned long long XML_Size;
#else
typedef int XML_Index;
typedef unsigned int XML_Size;
#endif /* XML_LARGE_SIZE */

Most compilers will support that, and those that don't can
still use the 32 bit API.

This will change the API like this:

XMLPARSEAPI(XML_Size) XML_GetCurrentLineNumber(XML_Parser parser);
XMLPARSEAPI(XML_Size) XML_GetCurrentColumnNumber(XML_Parser parser);
XMLPARSEAPI(XML_Index) XML_GetCurrentByteIndex(XML_Parser parser);
XMLPARSEAPI(XML_Size) XML_GetCurrentByteCount(XML_Parser parser);

Note: Even if XML_LARGE_SIZE is not defined, the above will change
the return type of XML_GetCurrentLineNumber, XML_GetCurrentColumnNumber
and XML_GetCurrentByteCount from int to uint! Could this be a problem?

What do you think?
I'd like to post a test release (for feedback purposes) soon.

Karl