According to the POSIX standard the option value is a pointer to void
and the option length a socklen_t. The Windows implementation makes the
option value be a pointer to character and the option length an int.
Casting the option value to a pointer to void conforms to the POSIX
standard while the implicit cast to a pointer to character conforms to
the Windows implementation.
The casts of the option length to the socklen_t data type conforms to
the POSIX standard. The socklen_t data type is actually an alias of an
int so it also conforms to the Windows implementation.
