[v3] Handle C++11 <math.h> overloads on Solaris 12

[Jonathan Wakely]

On 24/11/15 12:35 +0000, Jonathan Wakely wrote:
>Ah yes, because there's a using std::acosh, which puts Solaris' new

Oops, I meant "using ::acosh" not "using std::acosh" (the latter
wouldn't work in C++03 mode).