+NB: you risk to get quite a few warnings about "ANSI C++ forbids implicit
+ conversion from 'void *'" in all places where va_arg macro is used. This
+ is due to a bug in (some versions of) mingw32 headers which may be
+ corrected by editing the file
+
+ ${install_prefix}/lib/gcc-lib/i586-mingw32/egcs-2.91.57/include/stdarg.h
+
+ (instead of egcs-2.91.57 you may have something different), searching for
+ the lines
+
+/* Define __gnuc_va_list. */
+
+#ifndef __GNUC_VA_LIST
+#define __GNUC_VA_LIST
+#if defined(__svr4__) || defined(_AIX) || defined(_M_UNIX) || defined(__NetBSD__)
+typedef char *__gnuc_va_list;
+#else
+typedef void *__gnuc_va_list;
+#endif
+#endif
+
+ and adding "|| defined(_WIN32)" to the list of platforms on which
+ __gnuc_va_list is char *.
+