* m4/gnulib-cache.m4: Add `inet_ntop' and `inet_pton'.
* configure.ac: Don't check for `inet_ntop' and `inet_pton'.
* libguile/socket.c (scm_inet_pton, scm_inet_ntop): Compile regardless
of `HAVE_INET_PTON' and `HAVE_INET_NTOP' respectively.
* libguile/filesys.c: Use <stdlib.h> instead of <canonicalize.h>.
