Hi,
as described in the PR 69881 it happens quite often that cstddef is
called with __need_size_t because we still support gmp-4.3.2 which
is installed by contrib/download_prerequisites. This causes a kind
of undefined behavior. It is just by chance that this does not cause
the gcc-6 boot-strap to fail, but it causes gcc-4.9 bootstrap to fail
when the gcc-6 version of cstddef is around. So it looks like a
regression, because the new cstddef is more fragile than before.
As it looks like, neither c/* nor c_std/* headers will compile without
major bug-fixing first, and they are likely not in use by anybody.
Therefore I think it is best not to touch these at all, because it is
hard to test anything there.
So I propose to undefine all problematic __need_* that may cause
cstddef or cstdarg fail to compile.
Boot-strapped and reg-tested on x86_64-pc-linux-gnu
OK for trunk?
Thanks
Bernd.
2016-02-23 Bernd Edlinger <bernd.edlin...@hotmail.de>
PR libstdc++/69881
* include/c_global/cstdarg: Undefine __need___va_list.
* include/c_global/cstddef: Undefine all kinds of __need_*.
Index: libstdc++-v3/include/c_global/cstdarg
===================================================================
--- libstdc++-v3/include/c_global/cstdarg (revision 233604)
+++ libstdc++-v3/include/c_global/cstdarg (working copy)
@@ -38,6 +38,7 @@
#pragma GCC system_header
+#undef __need___va_list
#include <bits/c++config.h>
#include <stdarg.h>
Index: libstdc++-v3/include/c_global/cstddef
===================================================================
--- libstdc++-v3/include/c_global/cstddef (revision 233604)
+++ libstdc++-v3/include/c_global/cstddef (working copy)
@@ -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>
