Replaced "select" with "poll" for non-Windows Platforms - #2

#include <poll.h>
...
// return true if socket has data waiting to be read
bool datawaiting( int sock )
{
#ifdef _WIN32
	fd_set fds;
	FD_ZERO( &fds );
	FD_SET( sock, &fds );

	struct timeval tv;
	tv.tv_sec = 0;
	tv.tv_usec = 0;

	int r = select( sock+1, &fds, NULL, NULL, &tv);
	if (r < 0)
		BailOnSocketError( "select" );

	return FD_ISSET( sock, &fds ) != 0;
#else
	struct pollfd pfd;
	pfd.fd = sock;
	pfd.events = POLLIN;
	pfd.revents = 0;

	int r = poll( &pfd, 1, 0 );
	if (r < 0)
		BailOnSocketError( "poll" );

	return ( pfd.revents & POLLIN ) != 0;
#endif
}