configure: ensure sizeof(int) >= 4

configure: ensure sizeof(int) >= 4

There are multiple places we make this assumption. For example, in
source3/lib/tldap.c, we have this line

      if (ld->msgid == 2147483647) {

where ld->msgid is an int. And in librpc/idl/security.idl we have
several lines like:

      const int SEC_MASK_GENERIC        = 0xF0000000;

In lib/replace/inet_pton.c and inet_ntop.c we have

  /*
   * WARNING: Don't even consider trying to compile this on a system where
   * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
   */

but no attempt to enforce that as far as I can see, until now.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Tue Jul 11 22:44:15 UTC 2023 on atb-devel-224