* Makefile.in: Remove cygserver stuff.

* acconfig.h: Add USE_CYGSERVER define.
* config.h.in: Regenerate.
* configure.in: Add --enable-server setting.
* configure: Regenerate.
* fhandler_tty.cc (fhandler_tty_slave::open): Conditionalize compilation of
cygserver stuff.
* fork.cc (fork_child): Ditto.
* shm.cc: Ditto.
* tty.cc (tty::common_init): Ditto.
* dcrt0.cc: Use bool rather than BOOL for CYGWIN environment variable
definitions.
* environ.cc: Ditto.
* ntea.cc: Ditto.
* security.cc: Ditto.
* security.h: Ditto.
* syscalls.cc (check_posix_perm): Remove externs that were already declared in
a header.
* winsup.h: Ditto.  Declare _MT_SAFE here.  Delete it someday since cygwin
should always be _MT_SAFE.

winsup/cygwin/tty.cc

@@ -407,11 +407,16 @@ tty::common_init (fhandler_pty_master *ptym)
    */
   if (wincap.has_security ())
     {
+#ifdef USE_CYGSERVER
       if (cygserver_running == CYGSERVER_UNKNOWN)
 	cygserver_init ();
+#endif
 
-      if (cygserver_running != CYGSERVER_OK
-	  && !SetKernelObjectSecurity (hMainProc,
+      if (
+#ifdef USE_CYGSERVER
+	  cygserver_running != CYGSERVER_OK &&
+#endif
+	  !SetKernelObjectSecurity (hMainProc,
 				       DACL_SECURITY_INFORMATION,
 				       get_null_sd ()))
 	system_printf ("Can't set process security, %E");