remove c++11 requirement and -Werror=sign-compare

used static_cast<signed int> around WSA_WAIT_FAILED as it is an unsigned implicitly defined as (0xFFFFFFFF ion winbase.h) and causes a comparison error.

removed use of c++11 style initialiser list for 'sockaddr addr { 0 }' and changed it to 'sockaddr addr = { 0 }'

src/select.cpp

@@ -434,7 +434,7 @@ bool zmq::select_t::is_retired_fd (const fd_entry_t &entry)
 #if defined ZMQ_HAVE_WINDOWS
 u_short zmq::select_t::get_fd_family (fd_t fd_)
 {
-    sockaddr addr{ 0 };
+    sockaddr addr = { 0 };
     int addr_size = sizeof addr;
     int rc = getsockname (fd_, &addr, &addr_size);