Created attachment 918972 [details]
Upstream fix http://reviews.llvm.org/rL201729

Description of problem:

After gcc was updated to 4.9, clang is no longer able to compile cstddef. For example, this simple program:

--------------------------------
#include <boost/format.hpp>

int main(int argc, char **argv[]) {
    auto s = boost::format("");
    return 0;
}
--------------------------------

compiled with "clang++ -std=c++11 test.cpp" results in the following error:

--------------------------------
In file included from test.cpp:1:
In file included from /usr/include/boost/format.hpp:19:
In file included from /usr/include/boost/detail/workaround.hpp:41:
In file included from /usr/include/boost/config.hpp:40:
In file included from /usr/include/boost/config/select_stdlib_config.hpp:18:
/usr/bin/../lib/gcc/x86_64-redhat-linux/4.9.0/../../../../include/c++/4.9.0/cstddef:51:11: error: 
      no member named 'max_align_t' in the global namespace
  using ::max_align_t;
        ~~^
test.cpp:3:5: error: second parameter of 'main' (argument array) must be of type
      'char **'
int main(int argc, char **argv[]) {
    ^
2 errors generated.
--------------------------------


Version-Release number of selected component (if applicable):

gcc-4.9.0-15.fc21.x86_64
clang-3.4-11.fc21.x86_64


Additional info:

This has already been fixed upstream at http://reviews.llvm.org/rL201729 and it applies cleanly to the clang-3.4 sources. I've attached a copy of the upstream diff to this bug report.

(More info at Arch Linux bug tracker too: https://bugs.archlinux.org/task/40229)