[Bug libstdc++/69881] with gcc-6 of today building gcc-4.9 fails

[bernd.edlinger at hotmail dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69881

--- Comment #2 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
Something like that might be needed?

Index: c_global/cstddef
===================================================================
--- c_global/cstddef    (Revision 233574)
+++ c_global/cstddef    (Arbeitskopie)
@@ -41,6 +41,13 @@

 #pragma GCC system_header

+#if defined(__need_wchar_t) || defined(__need_size_t) \
+    || defined(__need_ptrdiff_t) || defined(__need_NULL) \
+    || defined(__need_wint_t)
+
+#include <stddef.h>
+
+#else
 #include <bits/c++config.h>
 #include <stddef.h>

@@ -51,5 +58,6 @@
   using ::max_align_t;
 }
 #endif
+#endif

 #endif // _GLIBCXX_CSTDDEF
Index: c_std/cstddef
===================================================================
--- c_std/cstddef       (Revision 233574)
+++ c_std/cstddef       (Arbeitskopie)
@@ -41,6 +41,13 @@

 #pragma GCC system_header

+#if defined(__need_wchar_t) || defined(__need_size_t) \
+    || defined(__need_ptrdiff_t) || defined(__need_NULL) \
+    || defined(__need_wint_t)
+
+#include <stddef.h>
+
+#else
 #include <bits/c++config.h>
 #include <stddef.h>

@@ -51,5 +58,6 @@
   using ::max_align_t;
 }
 #endif
+#endif

 #endif // _GLIBCXX_CSTDDEF


Question:

why are the both files different?
diff c_global/cstddef c_std/cstddef
26c26
<  *  This is a Standard C++ Library file.  You should @c \#include this file
---
>  *  This is a Standard C++ Library file.  You should @c #include this file