Tweak inet_ntop's signature to match POSIX.

[sunfishcode]

This changes inet_ntop's size parameter from size_t to socklen_t, following POSIX:

http://pubs.opengroup.org/onlinepubs/9699919799/functions/inet_ntop.html

In cloudlibc, these are typedefs for the same type, so there's no effective change here.

[EdSchouten]

The use of size_t is sort of intentional here.

POSIX added socklen_t to introduce portability between systems that use int (BSD & ...) and some that use size_t (QNX & ...). In my opinion it is a moronic type that should not have existed; code should have used size_t to begin with. You typically assign it to values obtained from sizeof(). Negative values are simply impossible. This is why cloudlibc declares it as size_t.

Even though cloudlibc declares socklen_t, it doesn't use it anywhere:

$ git grep socklen_t
src/include/netdb.h:typedef __size_t socklen_t;
src/include/sys/socket.h:typedef __size_t socklen_t;

This is because none of the code in cloudlibc has been designed to deal with these types being anything other than size_t. For example, it may well be the case that if socklen_t would be redefined to be smaller than size_t or become signed, we may run into bugs in functions that have socklen_t parameters (e.g., missing bounds checking, negative array indexing). By simply using size_t all over the place, we will cause explicit compiler errors if our assumptions would no longer hold.

[sunfishcode]

Makes sense, thanks for the explanation!