There are two "autoconf" config files: one for Unix systems (Xerces_autoconf_config.hpp),
and one for MSVC (Xerces_autoconf_config.msvc.hpp). The one for Unix systems is created by running
"./configure", but we're CMake-based so we use a sensible, configure generated file that we then tweak by hand.

The XercesDefs.hpp file was thus modified from including this:

#include	<xercesc/util/Xerces_autoconf_config.hpp>

to including this:

#if defined(_MSC_VER)
#   include	<xercesc/util/Xerces_autoconf_config.msvc.hpp>
#else
#   include	<xercesc/util/Xerces_autoconf_config.hpp>
#endif



