* cygserver.h (CYGWIN_SERVER_VERSION_API): Bump.
(request_code_t): Define CYGSERVER_REQUEST_SETPWD request type.
* cygserver_msg.h (client_request_msg::retval): Use default value of -1
for retval if msglen is 0.
* cygserver_sem.h (client_request_sem::retval): Ditto.
* cygserver_shm.h (client_request_shm::retval): Ditto.
* cygserver_setpwd.h: New file.
* external.cc (cygwin_internal): Implement new CW_SET_PRIV_KEY type.
* sec_auth.cc (open_local_policy): Make externally available.
Get ACCESS_MASK as argument.
(create_token): Accommodate change to open_local_policy.
(lsaauth): Ditto.
(lsaprivkeyauth): New function fetching token by retrieving
password stored in Cygwin or Interix LSA private data area and
calling LogonUser with it.
* security.h (lsaprivkeyauth): Declare.
(open_local_policy): Declare.
* setlsapwd.cc: New file implementing setting LSA private data password
using LsaStorePrivateData or by calling cygserver if available.
* syscalls.cc (seteuid32): Add workaround to get the original token
when switching back to the original privileged user, even if
setgroups group list is still active. Add long comment to explain why.
Call lsaprivkeyauth first, only if that fails call lsaauth or
create_token.
* include/cygwin/version.h: Bump API minor number.
* include/sys/cygwin.h (cygwin_getinfo_types): Add CW_SET_PRIV_KEY.
