update enabled status of undo/redo actions in the editor * file-editor-tab.h: new inline function returning the qscintilla edit area * octave-qscintilla.cc (constructor): connect textChanged signal to new private slot text_changed; (text_changed): new slot emitting a signal on undo/redo availability * octave-qscintilla.h: new slot and new signal * file-editor.cc (edit_status_update): new slot for updating undo/redo actions; (construct): undo/redo actions disabled at the beginning; (add_new_edit_tab): connect new slot to the signal from the qscintilla edit area indicating undo/redo availability * file-editor.h: new slot

include $(top_srcdir)/libinterp/link-deps.mk

if AMCOND_ENABLE_DYNAMIC_LINKING
  LIBOCTGUI_LINK_DEPS =
else
  LIBOCTGUI_LINK_DEPS = $(DLDFCN_LIBS)
endif

LIBOCTGUI_LINK_DEPS += \
  @QT_LIBS@

LIBOCTGUI_LINK_OPTS = \
  @QT_LDFLAGS@

if AMCOND_LINK_ALL_DEPS
  LIBOCTGUI_LINK_DEPS += $(LIBOCTINTERP_LINK_DEPS)
  LIBOCTGUI_LINK_OPTS += $(LIBOCTINTERP_LINK_OPTS)

  OCTAVE_GUI_LINK_DEPS = $(LIBOCTGUI_LINK_DEPS)
  OCTAVE_GUI_LINK_OPTS = $(LIBOCTGUI_LINK_OPTS)
endif