Test failures on Clang 3.0 with -std=c++11

[Nikita Kniazev]

e.g. http://www.boost.org/development/tests/develop/developer/output/teeks99-02-dc3-0-11-Docker-64on64-boost-bin-v2-libs-fusion-test-adapt_adt-test-clang-gnu-linux-3-0~c++11-debug-threadapi-pthread.html

  "clang++-3.0" -c -x c++ -Wno-c99-extensions -std=c++11 -O0 -g -fno-inline -Wall -g -fPIC -m64  -DBOOST_ALL_NO_LIB=1 -I".." -o "/var/boost/run/results/boost/bin.v2/libs/fusion/test/adapt_adt.test/clang-gnu-linux-3.0~c++11/debug/threadapi-pthread/sequence/adapt_adt.o" "../libs/fusion/test/sequence/adapt_adt.cpp"

In file included from ../libs/fusion/test/sequence/adapt_adt.cpp:16:
../boost/fusion/container/vector/vector.hpp:250:61: error: invalid use of 'this' outside of a nonstatic member function
            auto at_impl(J) -> decltype(at_detail<J::value>(this))
                                                            ^
../boost/fusion/container/vector/vector.hpp:251:13: error: type name requires a specifier or qualifier
            {
            ^
../boost/fusion/container/vector/vector.hpp:251:13: error: C++ requires a type specifier for all declarations
            {
            ^
../boost/fusion/container/vector/vector.hpp:250:13: error: 'auto' return without trailing return type
            auto at_impl(J) -> decltype(at_detail<J::value>(this))
            ^
../boost/fusion/container/vector/vector.hpp:257:67: error: invalid use of 'this' outside of a nonstatic member function
            auto at_impl(J) const -> decltype(at_detail<J::value>(this))
                                                                  ^
../boost/fusion/container/vector/vector.hpp:258:13: error: type name requires a specifier or qualifier
            {
            ^
../boost/fusion/container/vector/vector.hpp:258:13: error: C++ requires a type specifier for all declarations
            {
            ^
../boost/fusion/container/vector/vector.hpp:257:13: error: 'auto' return without trailing return type
            auto at_impl(J) const -> decltype(at_detail<J::value>(this))
            ^