src/w32.c: Include winioctl.h and aclapi.h.
(is_symlink, chase_symlinks, enable_privilege, restore_privilege)
(revert_to_self): Forward declarations of static functions.
<static BOOL g_b_init_get_security_info>:
<g_b_init_create_symbolic_link>: New static flags.
(globals_of_w32): Initialize them to zero.
(GetSecurityInfo_Proc, CreateSymbolicLink_Proc): New typedefs.
(map_w32_filename): Improve commentary. Simplify switch.
(SYMBOLIC_LINK_FLAG_DIRECTORY): Define if not defined in system
headers (most versions of MinGW w32api don't).
(get_security_info, create_symbolic_link)
(get_file_security_desc_by_handle, is_symlink, chase_symlinks):
New functions.
(sys_access, sys_chmod): Call 'chase_symlinks' to resolve symlinks
in the argument file name.
(sys_access): Call unc_volume_file_attributes only if
GetFileAttributes fails with network-related error codes.
(sys_rename): Diagnose renaming of a symlink when the user doesn't
have the required privileges.
(get_file_security_desc_by_name): Renamed from
get_file_security_desc.
(stat_worker): New function, with most of the guts of 'stat', and
with addition of handling of symlinks and support for 'lstat'. If
possible, get file's attributes and security information by
handle, not by name. Produce S_IFLNK bit for symlinks, when
called from 'lstat'.
(stat, lstat): New functions, call 'stat_worker'.
(symlink, readlink, careadlinkat): Rewritten to create and resolve
symlinks when the underlying filesystem supports them.
lib/src/ntlib.c (lstat): New function, calls 'stat'.
nt/inc/sys/stat.h (S_IFLNK): Define.
(S_ISLNK): A non-trivial definition.
(lstat): Prototype instead of a macro that redirects to 'stat'.
lisp/files.el (file-truename): Don't skip symlink-chasing part on
windows-nt. Incorporate the resolution of 8+3 short aliases on
Windows into the loop that recursively chases symlinks. Compare
directory and its parent case-insensitively on MS-Windows and
MS-DOS.
etc/NEWS: Announce the symlink support on MS-Windows.
inc/pwd.h (struct passwd): Change the types of pw_uid and pw_gid to unsigned.
(getpwuid): Argument is now unsigned.
uid_t is now unsigned.
ntlib.c (setuid): Argument is now unsigned.
(getuid): Return value is now unsigned.
(getpwuid): Argument is now unsigned.
(fchown): UID and GID arguments are now unsigned.
ntlib.h (fchown): UID and GID arguments are now unsigned.
(getuid): Return value is now unsigned.
(setuid): Argument is now unsigned.
(getpwuid): Remove prototype (it's declared in nt/inc/pwd.h).
w32.c (getpwuid): Change argument type to unsigned.
(struct w32_id): Change type of `rid' member to unsigned.
(w32_cached_id, w32_add_to_cache, get_name_and_id): Change type of
argument ID to unsigned. All callers changed.
(getuid, geteuid, getgid, getegid): Change return type to unsigned.
