This is a followup to edfca3b7e5, which
added the 'posix_spawnp' module but not 'posix_spawn'.
* m4/gnulib-cache.m4: Add 'posix_spawn' module.
* gnulib-local/m4/clock_time.m4.diff: Adjust.
* configure.ac: Move 'gl_EARLY' use right after 'AC_PROG_CC'.
* 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>.
