* guix/build/syscalls.scm (sockaddr-in,sockaddr-in6): Rename to ...
(sockaddr-in/linux, sockaddr-in6/linux): ... this. Rename introduced bindings
as well.
(write-socket-address!/linux,read-socket-address/linux): Rename from
(write-socket-address!, read-socket-address): ... new switches between those
and ...
(write-socket-address!/hurd, read-socket-address/hurd): ... these new function.