Cygwin: fork/exec: fix child process permissions

- Exec'ed/spawned processes don't need PROCESS_DUP_HANDLE.  Remove that
  permission from the parent handle.

- PROCESS_QUERY_LIMITED_INFORMATION doesn't work for Windows 7 if the
  process is started as a service.  Add PROCESS_QUERY_INFORMATION for
  pre-Windows 8 in that case.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/security.h

@@ -17,6 +17,7 @@ details. */
 
 /* UID/GID */
 void uinfo_init ();
+bool check_token_membership (HANDLE, PSID);
 bool check_token_membership (PSID);
 
 #define ILLEGAL_UID ((uid_t)-1)