described a patch to mingw32 headers to fix va_arg warnings

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4045 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

BuildCVS.txt

@@ -36,7 +36,7 @@ and its make.exe).
    where your compiler and tools reside
 
 b-2) Using Mingw32 with gcc-2.95 and Anders Norlander's
-	Win32 headers
+     Win32 headers
 
 Using the newer gcc-2.95/Noralander header combination
 will allow you to compile more of the MSW code, such
@@ -190,14 +190,37 @@ Type
 and wait, wait, wait. Don't leave the room, because the minute you do there
 will be a compile error :-)
 
+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 *.
+
 If this is successful, you end up with a libwx_msw.a in win32/lib.  Now try
 building the minimal sample:
 
 -> cd samples/minimal
 -> make
--> mv minimal minimal.exe
 
-and run it with wine, for example
+and run it with wine, for example (or copy to a Windows box)
 -> wine minimal.exe
 
 If all is well, do an install; from win32