In attempted recursive minibuffer use, display error message in correct frame

In attempted recursive minibuffer use, display error message in correct frame

This was problematic when minibuffer-follows-selected-frame was non-nil.
Introduce a new parameter DONT-SET-FRAME to set-window-configuration.

* doc/lispref/windows.texi (Window Configurations): Describe the new &optional
parameter to set-window-configuration.

* etc/NEWS (Lisp Changes): Note the new parameter to set-window-configuration.

* src/keyboard.c (read_char_help_form_unwind): Add a new Qnil argument to the
call of Fset_window_configuration.

* src/minibuf.c (read_minibuf): Cons up a Qt with the window configuration in
the argument to record_unwind_protect for the window configuration (twice).

* src/window.c (Fset_window_configuration): Add the new &optional parameter
and document it in the doc string.  At the final do_switch_frame operation,
restore the original frame when DONT-SET-FRAME is non-nil.
(restore_window_configuration): Handle the new parameter when the supplied
argument is a cons.