* socket.c (scm_inet_aton, scm_inet_pton): Convert SCM strings to

* socket.c (scm_inet_aton, scm_inet_pton): Convert SCM strings to
locale strings instead of accessing their internals.
(scm_recv, scm_send, scm_recvfrom, scm_sendto): Use
SCM_I_STRING_CHARS and SCM_I_STRING_LENGTH instead of
SCM_STRING_CHARS and SCM_STRING_LENGTH.

* socket.c, rw.c, deprecated.h, validate.h
(SCM_VALIDATE_STRING_COPY): Deprecated.  Replaced all uses with
SCM_VALIDATE_STRING plus SCM_I_STRING_CHARS or
scm_to_locale_string, etc.
(SCM_VALIDATE_SUBSTRING_SPEC_COPY): Deprecated.  Replaced as
above, plus scm_i_get_substring_spec.