New upstream version 5.8

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+ttyctl [ -fu ]
+       The -f option freezes the tty (i.e. terminal or terminal  emula-
+       tor),  and  -u unfreezes it.  When the tty is frozen, no changes
+       made to the tty settings by external programs will be honored by
+       the  shell,  except  for  changes in the size of the screen; the
+       shell will simply reset the settings to their previous values as
+       soon as each command exits or is suspended.  Thus, stty and sim-
+       ilar programs have no effect when the tty is  frozen.   Freezing
+       the  tty  does not cause the current state to be remembered: in-
+       stead, it causes future changes to the state to be blocked.
+
+       Without options it reports whether the  terminal  is  frozen  or
+       not.
+
+       Note  that,  regardless of whether the tty is frozen or not, the
+       shell needs to change the settings when the line editor  starts,
+       so  unfreezing  the  tty does not guarantee settings made on the
+       command line are preserved.  Strings  of  commands  run  between
+       editing  the  command line will see a consistent tty state.  See
+       also the shell variable STTY for a means of initialising the tty
+       before running external commands.