src/w32.c: Include sddl.h and sys/acl.h.
(SDDL_REVISION_1): Define if not already defined.
(g_b_init_get_security_descriptor_dacl)
(g_b_init_convert_sd_to_sddl, g_b_init_convert_sddl_to_sd)
(g_b_init_is_valid_security_descriptor)
(g_b_init_set_file_security): New static flags.
(globals_of_w32): Initialize them to zero.
(SetFileSecurity_Name): New string constant.
(SetFileSecurity_Proc, GetSecurityDescriptorDacl_Proc)
(ConvertStringSecurityDescriptorToSecurityDescriptor_Proc)
(ConvertSecurityDescriptorToStringSecurityDescriptor_Proc)
(IsValidSecurityDescriptor_Proc): New typedefs.
(get_file_security, get_security_descriptor_owner)
(get_security_descriptor_group): Set errno to ENOTSUP.
(set_file_security, get_security_descriptor_dacl)
(is_valid_security_descriptor, convert_sd_to_sddl)
(convert_sddl_to_sd, acl_valid, acl_to_text, acl_from_text)
(acl_free, acl_get_file, acl_set_file): New functions.
src/fileio.c (Fcopy_file) [WINDOWSNT]: Support copying ACLs.
nt/inc/sys/acl.h: New file.
nt/inc/ms-w32.h (ENOTSUP): Define if undefined.
nt/config.nt (HAVE_POSIX_ACL): Define.
doc/lispref/files.texi (File Attributes, Changing Files): Update to include
MS-Windows support for ACLs.
