acl: Add support for ACLs on NonStop Kernel.

acl: Add support for ACLs on NonStop Kernel.

* m4/acl.m4 (gl_FUNC_ACL): For Solaris, test for facl(), not for acl().
Check whether the function aclsort() exists.
* lib/acl-internal.h: For Solaris, test HAVE_FACL, not HAVE_ACL.
(acl_nontrivial) [HAVE_ACLSORT]: New declaration.
* lib/file-has-acl.c: For Solaris, test HAVE_FACL, not HAVE_ACL.
(acl_nontrivial [HAVE_ACLSORT]: New function.
(file_has_acl): Implement for NonStop Kernel.
* lib/set-mode-acl.c: For Solaris, test HAVE_FACL, not HAVE_ACL.
(qset_acl): Implement for NonStop Kernel.
* lib/copy-acl.c (qcopy_acl): Implement for NonStop Kernel.
* tests/test-sameacls.c: For Solaris, test HAVE_FACL, not HAVE_ACL.
(main): Implement for NonStop Kernel.
* tests/test-file-has-acl.sh (acl_flavor): Set to 'nsk' on NonStop
Kernel. Handle this flavor.
* tests/test-set-mode-acl.sh: Likewise.
* tests/test-copy-acl.sh: Likewise.
* tests/test-copy-file.sh: Likewise.