Apple clang 3.1 using libc++ needs <numeric> for std::accumulate.
Apple clang 3.1 using libc++ needs <numeric> for std::accumulate.

Poulpy21/vexcl,kapadia/vexcl,ddemidov/vexcl,ddemidov/vexcl,Poulpy21/vexcl,Poulpy21/vexcl,kapadia/vexcl