std::max causes compilation error on Windows

[cacharle]

There is one use of std::max that doesn't use the (std::max) trick when the max macro is defined by Windows.

cppzmq/zmq.hpp

Line 2756 in 21c83ca

return static_cast<size_t>(std::max(rc, 0));

My current workaround is to add #define NOMINMAX to all my files but it would be nice if the library could handle it.