Add limited support for Solaris 10 ZFS-style ACLs: just enough to

Add limited support for Solaris 10 ZFS-style ACLs: just enough to
handle file_has_acl.
* lib/acl-internal.h, lib/acl_entries.c, lib/file-has-acl.c: New files.
* lib/acl.c: Move header inclusions and related macro defns into
lib/acl-internal.h.
(S_ISLNK): Remove defn, since that's now done for us.
(file_has_acl): Move to lib/file-has-acl.c.
Call acl_trivial if available.  This is the crucial part of the fix.
(acl_entries): Move to lib/acl_entries.c.  Now extern, since it's
shared within the library.  Rewrite a bit, partly to make it compatible
with the GNU coding style.
* m4/acl.m4 (AC_FUNC_ACL): Add AC_LIBOBJ([file-has-acl]).
Remove unnecessary double-quotes.
Don't test for acl_to_text; the build will catch that.
Replace acl_entries if it doesn't exist and it is needed.
Check for -lsec and acl_trivial (as used on Solaris 10).
* modules/acl (Files): Add lib/acl-internal.h, lib/acl_entries.c,
lib/file-has-acl.c.
(Depends-on): Add sys_stat, for S_ISLNK.