re PR libstdc++/69881 (with gcc-6 of today building gcc-4.9 fails)

2016-02-23  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        PR libstdc++/69881
        * include/c_global/cstdarg: Undefine __need___va_list.
        * include/c_global/cstddef: Undefine all kinds of __need_*.

From-SVN: r233636

libstdc++-v3/ChangeLog

+2016-02-23  Bernd Edlinger  <bernd.edlinger@hotmail.de>
+
+	PR libstdc++/69881
+	* include/c_global/cstdarg: Undefine __need___va_list.
+	* include/c_global/cstddef: Undefine all kinds of __need_*.
+
 2016-02-16  Tim Shen  <timshen@google.com>
 
 	PR libstdc++/69794

libstdc++-v3/include/c_global/cstdarg

@@ -38,6 +38,7 @@
 
 #pragma GCC system_header
 
+#undef __need___va_list
 #include <bits/c++config.h>
 #include <stdarg.h>
 

libstdc++-v3/include/c_global/cstddef

@@ -41,6 +41,11 @@
 
 #pragma GCC system_header
 
+#undef __need_wchar_t
+#undef __need_ptrdiff_t
+#undef __need_size_t
+#undef __need_NULL
+#undef __need_wint_t
 #include <bits/c++config.h>
 #include <stddef.h>