Increase FD_SETSIZE

The maximum number of sockets which a Windows Sockets application can make use of is determined at compile time by the manifest constant FD_SETSIZE. This value is used in constructing the fd_set structures used in select(). The default value in winsock.h is 64. If an application is designed to be capable of working with more than 64 sockets, the implementor should define the manifest FD_SETSIZE in every source file before including winsock.h or winsock2.h. One way of doing this may be to include the definition within the compiler options in the makefile, for example adding -DFD_SETSIZE=128 as an option to the compiler command line for Microsoft C. It must be emphasized that defining FD_SETSIZE as a particular value has no effect on the actual number of sockets provided by a Windows Sockets implementation.