fixed problem in xmlTextWriterVSprintf caused by misuse of vsnprintf added * xmlwriter.c: fixed problem in xmlTextWriterVSprintf caused by misuse of vsnprintf * configure.in, config.h.in: added a configuration check for va_copy and added a define for VA_COPY for xmlwriter.c fix * parser.c: fixed problem with CRLF split between chunks (bug #319279) (fix provided by Brion Vibber)