integrate Qt graphics toolkit in Qt interpreter object Instead of dynamically loading Qt graphics toolkit, make it an integral part of the Qt interpreter object. This arrangement allows us to pass references to both the Octave interpreter and the base_qobject to the graphics subsystem. Earlier, I made the Qt graphics system loadable so that it was more like the fltk and gnuplot versions. But that doesn't really make sense, as the Qt graphics system requires a Qt application context and specific support from Octave for callbacks and other things. It can't really be separated from Octave itself, or the parts of Octave that are built on Qt, so it might as well be available and initialized any time that we start a copy of Octave that is using Qt (i.e., not the strictly "cli" version that doesn't link to the Qt libraries). * __init_qt__.h, __init_qt__.cc: Delete. * graphics/module.mk: Update. Create convenience library for libgraphics instead of __init_qt__.oct file. * libgui/module.mk (%canon_reldir%_liboctgui_la_LIBADD): Add libgraphics.la to the list. * graphics-init.h, graphics-init.cc: New files. (graphics_init): New function to initialize the graphics system. * libgui/src/module.mk: Update. Add -I options for libgui/graphics directories to CPPFLAGS. * interpreter-qobject.cc (interpreter_qobject::interpreter_qobject): Call graphics_init to initialize graphics system.

--- a/libgui/src/module.mk	Tue Nov 05 13:28:45 2019 -0500
+++ b/libgui/src/module.mk	Tue Nov 05 18:23:20 2019 -0500
@@ -203,6 +203,7 @@
   %reldir%/gui-settings.h \
   %reldir%/external-editor-interface.h \
   %reldir%/files-dock-widget.h \
+  %reldir%/graphics-init.h \
   %reldir%/history-dock-widget.h \
   %reldir%/interpreter-qobject.h \
   %reldir%/m-editor/file-editor-interface.h \
@@ -241,6 +242,7 @@
   %reldir%/dw-main-window.cc \
   %reldir%/external-editor-interface.cc \
   %reldir%/files-dock-widget.cc \
+  %reldir%/graphics-init.cc \
   %reldir%/gui-settings.cc \
   %reldir%/history-dock-widget.cc \
   %reldir%/interpreter-qobject.cc \
@@ -284,6 +286,7 @@
   @QT_CPPFLAGS@ \
   -I$(srcdir)/libgui/qterminal/libqterminal \
   -Ilibgui/src -I$(srcdir)/libgui/src \
+  -Ilibgui/graphics -I$(srcdir)/libgui/graphics \
   -I$(srcdir)/%reldir%/m-editor \
   -Iliboctave \
   -I$(srcdir)/liboctave/array \