games/xevil: unbreak build with Clang 6 (C++14 by default)

libc++ doesn't like "using namespace std" in C++11

role.cpp:656:62: error: invalid operands to binary expression ('__bind<int &, sockaddr *, unsigned long>' and 'int')

if (bind(udpSock,(CMN_SOCKADDR *)&client,sizeof(client)) >= 0) {
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~

role.cpp:1829:70: error: invalid operands to binary expression ('__bind<int &, sockaddr *, unsigned long>' and 'int')

if (bind(tcpSock, (CMN_SOCKADDR *)&serverAddr, sizeof(serverAddr)) < 0) {
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~

role.cpp:1836:70: error: invalid operands to binary expression ('__bind<int &, sockaddr *, unsigned long>' and 'int')

if (bind(udpSock, (CMN_SOCKADDR *)&serverAddr, sizeof(serverAddr)) < 0) {
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~

serverping.cpp:173:60: error: invalid operands to binary expression ('__bind<int &, sockaddr *, unsigned long>' and 'int')

if (bind(udpSock,(CMN_SOCKADDR *)&client,sizeof(client)) < 0) {
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~

Reported by: pkg-fallout