allow release notes window to be opened from command line * main-window.h, main-window.cc (main_window::m_release_notes_windoow, main_window::m_release_notes_icon): Delete member variables and all uses. (main_window::display_release_notes): Delete. (main_window::show_release_notes_signal): New signal. (main_window::construct_news_menu): Use lambda function to emit show_release_notes_signal. * release-notes.h, release-notes.cc: New files. * libgui/src/module.mk: Update. * octave-qobject.h, octave-qobject.cc (base_qobject::base_qobject): Connect main_window show_release_notes_signal to base_qobject show_release_notes slot. If gui_app is true, connect main_window show_release_notes_signal to base_qobject show_release_notes slot. (base_qobject::start_gui): Also connect main_window show_release_notes_signal to base_qobject show_release_notes slot here. (base_qobject::m_release_notes): New member variable. (base_qobject::release_notes_widget, base_qobject::show_release_notes): New functions. * qt-interpreter-events.h, qt-interpreter-events.cc (qt_interpreter_events::show_release_notes): New function. (qt_interpreter_events::show_release_notes_signal): New signal. * event-manager.h, event-manager.cc (event_manager::show_release_notes): New function. (interpreter_events::show_release_notes): New virtual function. (F__event_manager_show_release_notes__): New function.

--- a/libgui/src/module.mk	Fri Jun 25 17:27:17 2021 -0400
+++ b/libgui/src/module.mk	Sat Jun 26 07:59:17 2021 -0400
@@ -149,6 +149,7 @@
   %reldir%/moc-main-window.cc \
   %reldir%/moc-news-reader.cc \
   %reldir%/moc-octave-qobject.cc \
+  %reldir%/moc-release-notes.cc \
   %reldir%/moc-settings-dialog.cc \
   %reldir%/moc-terminal-dock-widget.cc \
   %reldir%/moc-color-picker.cc \
@@ -235,6 +236,7 @@
   %reldir%/qt-application.h \
   %reldir%/qt-interpreter-events.h \
   %reldir%/qt-utils.h \
+  %reldir%/release-notes.h \
   %reldir%/resource-manager.h \
   %reldir%/settings-dialog.h \
   %reldir%/shortcut-manager.h \
@@ -280,6 +282,7 @@
   %reldir%/octave-qobject.cc \
   %reldir%/qt-interpreter-events.cc \
   %reldir%/qt-application.cc \
+  %reldir%/release-notes.cc \
   %reldir%/resource-manager.cc \
   %reldir%/settings-dialog.cc \
   %reldir%/shortcut-manager.cc \