for new path API.
* security.sgml: New file to document cygwin_set_impersonation_token
and cygwin_logon_user with only eight years of delay.
* shared.sgml: Remove file.
* include/sys/cygwin.h (cygwin32_attach_handle_to_fd): Move declaration
into fully deprecated function block.
(cygwin_logon_user): Move declaration down to declaration of
cygwin_set_impersonation_token.
