changeset 28300:0c6dcf803529

Remove support for Qt4 in Octave 7. * configure.ac: Change QT_VERSIONS variable to just "5". * m4/acinclude.m4 (OCTAVE_CHECK_FUNC_QABSTRACTITEMMODEL_BEGINRESETMODEL, OCTAVE_CHECK_FUNC_QCOMBOBOX_SETCURRENTTEXT, OCTAVE_CHECK_FUNC_QHEADERVIEW_SETSECTIONRESIZEMODE, OCTAVE_CHECK_FUNC_QHEADERVIEW_SETSECTIONSCLICKABLE, OCTAVE_CHECK_FUNC_QHEADERVIEW_SETSECTIONSMOVABLE, OCTAVE_CHECK_FUNC_QINSTALLMESSAGEHANDLER, OCTAVE_CHECK_FUNC_QLINEEDIT_SETPLACEHOLDERTEXT, OCTAVE_CHECK_FUNC_QMOUSEEVENT_LOCALPOS, OCTAVE_CHECK_FUNC_QOBJECT_FINDCHILDREN_ACCEPTS_FINDCHILDOPTIONS, OCTAVE_CHECK_FUNC_QTABWIDGET_SETMOVABLE, OCTAVE_CHECK_FUNC_QWHEELEVENT_ANGLEDELTA, OCTAVE_CHECK_FUNC_QTMESSAGEHANDLER_ACCEPTS_QMESSAGELOGCONTEXT, OCTAVE_CHECK_MEMBER_QFONT_FORCE_INTEGER_METRICS, OCTAVE_CHECK_MEMBER_QFONT_MONOSPACE, OCTAVE_HAVE_QGUIAPPLICATION): Remove obsolete macros * m4/acinclude.m4 (HAVE_QT_SCINTILLA): Remove option '4' in case statement for Qt version. * m4/acinclude.m4 (OCTAVE_HAVE_QT): Remove test for Qt4 and AC_DEFINE for HAVE_QT. * m4/acinclude.m4 (OCTAVE_CHECK_QT_VERSION): Remove option '4' in case statement for $qt_version. Remove test for $qt_version = 4 calling pkg_config. Delete calls to macros that were removed. * Canvas.cc (select_object): Remove HAVE_QMOUSEEVENT_LOCALPOS conditionals. * QtHandlesUtils.cc (makeScrollEventStruct): Remove HAVE_QWHEELEVENT_ANGLEDELTA conditional. * Table.cc (updateEnable, updateRearrangeableColumns): Remove HAVE_QT4 conditional. * files-dock-widget.cc (files_dock_widget): Remove HAVE_QHEADERVIEW_SETSECTIONSCLICKABLE conditional. * find-files-dialog.cc (find_files_dialog): Remove HAVE_QHEADERVIEW_SETSECTIONSCLICKABLE conditional. * file-editor.cc (file_editor_tab_widget): Remove HAVE_QTABWIDGET_SETMOVABLE conditional. * find-dialog.cc (init_search_text): Remove HAVE_QCOMBOBOX_SETCURRENTTEXT conditional. * main-window.cc (display_community_news): Remove QOBJECT_FINDCHILDREN_ACCEPTS_FINDCHILDOPTIONS conditional. * octave-qobject.cc (message_handler): Remove QTMESSAGEHANDLER_ACCEPTS_QMESSAGELOGCONTEXT conditional. * octave-qobject.cc (base_qobject): Remove HAVE_QINSTALLMESSAGEHANDLER, HAVE_QT4 conditionals. * resource-manager.cc (get_default_font_family): Remove HAVE_QFONT_MONOSPACE conditional. * shortcut-manager.cc (enter_shortcut::keyPressEvent): Remove HAVE_QGUIAPPLICATION conditional. * shortcut-manager.cc (shortcut_manager::fill_treewidget): Remove HAVE_QHEADERVIEW_SETSECTIONRESIZEMODE conditional. * tab-bar.cc (move_tab_left, move_tab_right, switch_tab): Remove HAVE_QTABWIDGET_SETMOVABLE conditional. * variable-editor.cc (variable_dock_widget, change_floating, change_fullscreen): Remove HAVE_QGUIAPPLICATION conditional. * variable-editor.cc (variable_editor_view, setModel): Remove HAVE_QHEADERVIEW_SETSECTIONRESIZEMODE conditional. * variable-editor.cc (construct_tool_bar): Remove QOBJECT_FINDCHILDREN_ACCEPTS_FINDCHILDOPTIONS conditional. * variable-editor.h (class variable_dock_widget): Remove HAVE_QGUIAPPLICATION conditional. * workspace-view.cc (workspace_view): Remove HAVE_QHEADERVIEW_SETSECTIONSCLICKABLE conditionals.
author Rik <rik@octave.org>
date Sat, 16 May 2020 13:32:24 -0700
parents a8f6a7083428
children b8a38ed00bf4
files configure.ac libgui/graphics/Canvas.cc libgui/graphics/QtHandlesUtils.cc libgui/graphics/Table.cc libgui/src/files-dock-widget.cc libgui/src/find-files-dialog.cc libgui/src/m-editor/file-editor.cc libgui/src/m-editor/find-dialog.cc libgui/src/main-window.cc libgui/src/octave-qobject.cc libgui/src/resource-manager.cc libgui/src/shortcut-manager.cc libgui/src/tab-bar.cc libgui/src/variable-editor.cc libgui/src/variable-editor.h libgui/src/workspace-view.cc m4/acinclude.m4
diffstat 17 files changed, 2 insertions(+), 658 deletions(-) [+]
line wrap: on
line diff
--- a/configure.ac	Sat May 16 11:09:09 2020 -0700
+++ b/configure.ac	Sat May 16 13:32:24 2020 -0700
@@ -1843,7 +1843,7 @@
 
 ### GUI/Qt related tests.
 
-QT_VERSIONS="5 4"
+QT_VERSIONS="5"
 
 AC_ARG_WITH([qt],
   [AS_HELP_STRING([--with-qt=VER], [use the Qt major version VER])
--- a/libgui/graphics/Canvas.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/graphics/Canvas.cc	Sat May 16 13:32:24 2020 -0700
@@ -371,11 +371,7 @@
 
             r.adjust (-5, -5, 5, 5);
 
-#if defined (HAVE_QMOUSEEVENT_LOCALPOS)
             bool rect_contains_pos = r.contains (event->localPos ());
-#else
-            bool rect_contains_pos = r.contains (event->posF ());
-#endif
             if (rect_contains_pos)
               {
                 currentObj = childObj;
@@ -429,11 +425,7 @@
                 // the axes and still select it.
                 r.adjust (-20, -20, 20, 20);
 
-#if defined (HAVE_QMOUSEEVENT_LOCALPOS)
                 bool rect_contains_pos = r.contains (event->localPos ());
-#else
-                bool rect_contains_pos = r.contains (event->posF ());
-#endif
                 if (rect_contains_pos)
                   axesObj = *it;
               }
--- a/libgui/graphics/QtHandlesUtils.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/graphics/QtHandlesUtils.cc	Sat May 16 13:32:24 2020 -0700
@@ -402,12 +402,7 @@
 
       // We assume a standard mouse with 15 degree steps and Qt returns
       // 1/8 of a degree.
-#if defined (HAVE_QWHEELEVENT_ANGLEDELTA)
       int ydelta = -(event->angleDelta().y ());
-#else
-      int ydelta = (event->orientation () == Qt::Vertical
-                    ? -(event->delta ()) : 0);
-#endif
       retval.setfield ("VerticalScrollCount", octave_value (ydelta / 120));
 
       // FIXME: Is there any way to access the number of lines a scroll step
--- a/libgui/graphics/Table.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/graphics/Table.cc	Sat May 16 13:32:24 2020 -0700
@@ -1321,11 +1321,7 @@
                                      : QAbstractItemView::NoSelection);
 
     // Set rearrangeablecolumns
-    #if defined (HAVE_QT4)
-      m_tableWidget->horizontalHeader ()->setMovable (enabled && rearrangeableColumns);
-    #elif defined (HAVE_QT5)
-      m_tableWidget->horizontalHeader ()->setSectionsMovable (enabled && rearrangeableColumns);
-    #endif
+    m_tableWidget->horizontalHeader ()->setSectionsMovable (enabled && rearrangeableColumns);
     m_tableWidget->horizontalHeader ()->setDragEnabled (enabled && rearrangeableColumns);
     m_tableWidget->horizontalHeader ()->setDragDropMode (QAbstractItemView::InternalMove);
 
@@ -1504,11 +1500,7 @@
     bool rearrangeableColumns = tp.is_rearrangeablecolumns ();
     bool enabled = tp.is_enable ();
 
-  #if defined (HAVE_QT4)
-    m_tableWidget->horizontalHeader ()->setMovable (enabled && rearrangeableColumns);
-  #elif defined (HAVE_QT5)
     m_tableWidget->horizontalHeader ()->setSectionsMovable (enabled && rearrangeableColumns);
-  #endif
     m_tableWidget->horizontalHeader ()->setDragEnabled (enabled && rearrangeableColumns);
     m_tableWidget->horizontalHeader ()->setDragDropMode (QAbstractItemView::InternalMove);
   }
--- a/libgui/src/files-dock-widget.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/files-dock-widget.cc	Sat May 16 13:32:24 2020 -0700
@@ -245,16 +245,8 @@
         (settings->value (fb_column_state.key).toByteArray ());
 
     // Set header properties for sorting
-#if defined (HAVE_QHEADERVIEW_SETSECTIONSCLICKABLE)
     m_file_tree_view->header ()->setSectionsClickable (true);
-#else
-    m_file_tree_view->header ()->setClickable (true);
-#endif
-#if defined (HAVE_QHEADERVIEW_SETSECTIONSMOVABLE)
     m_file_tree_view->header ()->setSectionsMovable (true);
-#else
-    m_file_tree_view->header ()->setMovable (true);
-#endif
     m_file_tree_view->header ()->setSortIndicatorShown (true);
 
     QStringList mru_dirs =
--- a/libgui/src/find-files-dialog.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/find-files-dialog.cc	Sat May 16 13:32:24 2020 -0700
@@ -126,11 +126,7 @@
     m_file_list->setSortingEnabled (true);
     m_file_list->horizontalHeader ()->restoreState (settings->value (ff_column_state.key).toByteArray ());
     m_file_list->horizontalHeader ()->setSortIndicatorShown (true);
-#if defined (HAVE_QHEADERVIEW_SETSECTIONSCLICKABLE)
     m_file_list->horizontalHeader ()->setSectionsClickable (true);
-#else
-    m_file_list->horizontalHeader ()->setClickable (true);
-#endif
     m_file_list->horizontalHeader ()->setStretchLastSection (true);
     m_file_list->sortByColumn (settings->value (ff_sort_files_by_column).toInt (),
                                static_cast<Qt::SortOrder>
--- a/libgui/src/m-editor/file-editor.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/m-editor/file-editor.cc	Sat May 16 13:32:24 2020 -0700
@@ -75,9 +75,7 @@
 
     setTabsClosable (true);
     setUsesScrollButtons (true);
-#if defined (HAVE_QTABWIDGET_SETMOVABLE)
     setMovable (true);
-#endif
   }
 
   tab_bar * file_editor_tab_widget::get_tab_bar (void) const
--- a/libgui/src/m-editor/find-dialog.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/m-editor/find-dialog.cc	Sat May 16 13:32:24 2020 -0700
@@ -381,21 +381,7 @@
         int lbeg, lend, cbeg, cend;
         _edit_area->getSelection (&lbeg,&cbeg,&lend,&cend);
         if (lbeg == lend)
-#if defined (HAVE_QCOMBOBOX_SETCURRENTTEXT)
           _search_line_edit->setCurrentText (_edit_area->selectedText ());
-#else
-          if (_search_line_edit->isEditable ())
-            {
-              _search_line_edit->setEditText (_edit_area->selectedText ());
-            }
-          else
-            {
-              int i = _search_line_edit->findText (_edit_area->selectedText ());
-
-              if (i > -1)
-                _search_line_edit->setCurrentIndex (i);
-            }
-#endif
       }
 
     // set focus to "Find what" and select all text
--- a/libgui/src/main-window.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/main-window.cc	Sat May 16 13:32:24 2020 -0700
@@ -767,9 +767,7 @@
         QTextBrowser *browser
 
           = m_community_news_window->findChild<QTextBrowser *>("OctaveNews"
-#if defined (QOBJECT_FINDCHILDREN_ACCEPTS_FINDCHILDOPTIONS)
                                                                , Qt::FindDirectChildrenOnly
-#endif
                                                               );
         if (browser)
           browser->setHtml (news);
--- a/libgui/src/octave-qobject.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/octave-qobject.cc	Sat May 16 13:32:24 2020 -0700
@@ -119,11 +119,7 @@
   // Disable all Qt messages by default.
 
   static void
-#if defined (QTMESSAGEHANDLER_ACCEPTS_QMESSAGELOGCONTEXT)
   message_handler (QtMsgType, const QMessageLogContext &, const QString &)
-#else
-  message_handler (QtMsgType, const char *)
-#endif
   { }
 
   //! Reimplement QApplication::notify.  Octave's own exceptions are
@@ -177,11 +173,7 @@
 
     if (show_gui_msgs.empty ())
       {
-#if defined (HAVE_QINSTALLMESSAGEHANDLER)
         qInstallMessageHandler (message_handler);
-#else
-        qInstallMsgHandler (message_handler);
-#endif
       }
 
     // Set the codec for all strings (before wizard or any GUI object)
@@ -189,10 +181,6 @@
     QTextCodec::setCodecForLocale (QTextCodec::codecForName ("UTF-8"));
 #endif
 
-#if defined (HAVE_QT4)
-    QTextCodec::setCodecForCStrings (QTextCodec::codecForName ("UTF-8"));
-#endif
-
     // Initialize global Qt application metadata.
 
     QCoreApplication::setApplicationName ("GNU Octave");
@@ -202,7 +190,6 @@
 
     qRegisterMetaType<octave_value_list> ("octave_value_list");
 
-
 // Bug #55940 (Disable App Nap on Mac)
 #if defined (Q_OS_MAC)
     // Mac App Nap feature causes pause() and sleep() to misbehave.
--- a/libgui/src/resource-manager.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/resource-manager.cc	Sat May 16 13:32:24 2020 -0700
@@ -216,13 +216,9 @@
   QString resource_manager::get_default_font_family (void)
   {
     // Get the default monospaced font
-#if defined (HAVE_QFONT_MONOSPACE)
     QFont fixed_font;
     fixed_font.setStyleHint (QFont::Monospace);
     QString default_family = fixed_font.defaultFamily ();
-#else
-    QString default_family = global_font_family;
-#endif
 
     std::string env_default_family = sys::env::getenv ("OCTAVE_DEFAULT_FONT");
     if (! env_default_family.empty ())
--- a/libgui/src/shortcut-manager.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/shortcut-manager.cc	Sat May 16 13:32:24 2020 -0700
@@ -75,11 +75,7 @@
         if (key == Qt::Key_unknown || key == 0)
           return;
 
-#if defined (HAVE_QGUIAPPLICATION)
         Qt::KeyboardModifiers modifiers = QGuiApplication::keyboardModifiers (); //e->modifiers ();
-#else
-        Qt::KeyboardModifiers modifiers = QApplication::keyboardModifiers (); //e->modifiers ();
-#endif
 
         if (m_shift_modifier || (modifiers & Qt::ShiftModifier))
           key += Qt::SHIFT;
@@ -372,11 +368,7 @@
     m_dialog = nullptr;
     m_level_hash.clear ();
 
-#if defined (HAVE_QHEADERVIEW_SETSECTIONRESIZEMODE)
     tree_view->header ()->setSectionResizeMode (QHeaderView::ResizeToContents);
-#else
-    tree_view->header ()->setResizeMode (QHeaderView::ResizeToContents);
-#endif
 
     QTreeWidgetItem *main = new QTreeWidgetItem (tree_view);
     main->setText (0, tr ("Global"));
--- a/libgui/src/tab-bar.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/tab-bar.cc	Sat May 16 13:32:24 2020 -0700
@@ -56,16 +56,12 @@
 
   void tab_bar::move_tab_left (void)
   {
-#if defined (HAVE_QTABWIDGET_SETMOVABLE)
     switch_tab (-1, true);
-#endif
   }
 
   void tab_bar::move_tab_right (void)
   {
-#if defined (HAVE_QTABWIDGET_SETMOVABLE)
     switch_tab (1, true);
-#endif
   }
 
   void tab_bar::switch_tab (int direction, bool movetab)
@@ -83,11 +79,9 @@
 
     if (movetab)
       {
-#if defined (HAVE_QTABWIDGET_SETMOVABLE)
         moveTab (old_pos, new_pos);
         setCurrentIndex (old_pos);
         setCurrentIndex (new_pos);
-#endif
       }
     else
       setCurrentIndex (new_pos);
--- a/libgui/src/variable-editor.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/variable-editor.cc	Sat May 16 13:32:24 2020 -0700
@@ -110,7 +110,6 @@
     connect (p, SIGNAL (visibilityChanged (bool)),
              this, SLOT (setVisible (bool)));
 
-#if defined (HAVE_QGUIAPPLICATION)
 #define DOCKED_FULLSCREEN_BUTTON_TOOLTIP "Fullscreen undock"
 #define UNDOCKED_FULLSCREEN_BUTTON_TOOLTIP "Fullscreen"
     // Add a fullscreen button
@@ -140,7 +139,6 @@
     if (first != nullptr)
       index = h_layout->indexOf (first);
     h_layout->insertWidget (index, fullscreen_button);
-#endif
 
     // Custom title bars cause loss of decorations, add a frame
     m_frame = new QFrame (this);
@@ -152,7 +150,6 @@
   void
   variable_dock_widget::change_floating (bool)
   {
-#if defined (HAVE_QGUIAPPLICATION)
     if (isFloating ())
       {
         if (m_full_screen)
@@ -166,7 +163,6 @@
       }
     else
       m_fullscreen_action->setToolTip (tr (UNDOCKED_FULLSCREEN_BUTTON_TOOLTIP));
-#endif
 
     setFloating (! isFloating ());
   }
@@ -216,7 +212,6 @@
   void
   variable_dock_widget::change_fullscreen (void)
   {
-#if defined (HAVE_QGUIAPPLICATION)
     resource_manager& rmgr = m_octave_qobj.get_resource_manager ();
 
     if (! m_full_screen)
@@ -256,7 +251,6 @@
       }
 #undef DOCKED_FULLSCREEN_BUTTON_TOOLTIP
 #undef UNDOCKED_FULLSCREEN_BUTTON_TOOLTIP
-#endif
   }
 
   void
@@ -500,11 +494,7 @@
     setHorizontalScrollMode (QAbstractItemView::ScrollPerPixel);
     setVerticalScrollMode (QAbstractItemView::ScrollPerPixel);
 
-#if defined (HAVE_QHEADERVIEW_SETSECTIONRESIZEMODE)
     verticalHeader ()->setSectionResizeMode (QHeaderView::Interactive);
-#else
-    verticalHeader ()->setResizeMode (QHeaderView::Interactive);
-#endif
   }
 
   void
@@ -512,11 +502,7 @@
   {
     QTableView::setModel (model);
 
-#if defined (HAVE_QHEADERVIEW_SETSECTIONRESIZEMODE)
     horizontalHeader ()->setSectionResizeMode (QHeaderView::Interactive);
-#else
-    horizontalHeader ()->setResizeMode (QHeaderView::Interactive);
-#endif
 
     m_var_model = parent ()->findChild<variable_editor_model *> ();
 
@@ -1664,9 +1650,7 @@
     // that restores active window and focus before acting.
     QList<HoverToolButton *> hbuttonlist
       = m_tool_bar->findChildren<HoverToolButton *> (""
-#if defined (QOBJECT_FINDCHILDREN_ACCEPTS_FINDCHILDOPTIONS)
                                                      , Qt::FindDirectChildrenOnly
-#endif
                                                     );
     for (int i = 0; i < hbuttonlist.size (); i++)
       {
@@ -1678,9 +1662,7 @@
 
     QList<ReturnFocusToolButton *> rfbuttonlist
       = m_tool_bar->findChildren<ReturnFocusToolButton *> (""
-#if defined (QOBJECT_FINDCHILDREN_ACCEPTS_FINDCHILDOPTIONS)
                                                            , Qt::FindDirectChildrenOnly
-#endif
                                                           );
     for (int i = 0; i < rfbuttonlist.size (); i++)
       {
--- a/libgui/src/variable-editor.h	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/variable-editor.h	Sat May 16 13:32:24 2020 -0700
@@ -86,8 +86,6 @@
 
     QFrame *m_frame;
 
-#if defined (HAVE_QGUIAPPLICATION)
-
     QAction *m_fullscreen_action;
 
     bool m_full_screen;
@@ -96,8 +94,6 @@
 
     QRect m_prev_geom;
 
-#endif
-
 // See Octave bug #53807 and https://bugreports.qt.io/browse/QTBUG-44813
 #define QTBUG_44813_FIX_VERSION 0x999999
   signals:
--- a/libgui/src/workspace-view.cc	Sat May 16 11:09:09 2020 -0700
+++ b/libgui/src/workspace-view.cc	Sat May 16 13:32:24 2020 -0700
@@ -120,16 +120,8 @@
           (settings->value (ws_column_state.key).toByteArray ());
 
         // Set header properties for sorting
-#if defined (HAVE_QHEADERVIEW_SETSECTIONSCLICKABLE)
         m_view->horizontalHeader ()->setSectionsClickable (true);
-#else
-        m_view->horizontalHeader ()->setClickable (true);
-#endif
-#if defined (HAVE_QHEADERVIEW_SETSECTIONSMOVABLE)
         m_view->horizontalHeader ()->setSectionsMovable (true);
-#else
-        m_view->horizontalHeader ()->setMovable (true);
-#endif
         m_view->horizontalHeader ()->setSortIndicator (
           settings->value (ws_sort_column).toInt (),
           static_cast<Qt::SortOrder> (settings->value (ws_sort_order).toUInt ()));
--- a/m4/acinclude.m4	Sat May 16 11:09:09 2020 -0700
+++ b/m4/acinclude.m4	Sat May 16 13:32:24 2020 -0700
@@ -301,86 +301,6 @@
   fi
 ])
 dnl
-dnl Check whether the Qt class QAbstractItemModel exists and has the
-dnl beginResetModel and endResetModel member functions.  These member
-dnl functions were introduced in Qt 4.6.
-dnl
-dnl FIXME: Delete this entirely when we can safely assume that Qt 4.6 or later
-dnl is in use everywhere, or when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QABSTRACTITEMMODEL_BEGINRESETMODEL], [
-  AC_CACHE_CHECK([for QAbstractItemModel::beginResetModel in <QAbstractItemModel>],
-    [octave_cv_func_qabstractitemmodel_beginresetmodel],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CXXFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QAbstractItemModel>
-        class item_model : public QAbstractItemModel
-        {
-        public:
-          item_model (QObject *parent = 0) : QAbstractItemModel (parent) {}
-          ~item_model () {}
-          QModelIndex index (int, int, const QModelIndex& m) const { return m; }
-          QModelIndex parent (const QModelIndex& m) const { return m; }
-          int columnCount (const QModelIndex&) const { return 0; }
-          int rowCount (const QModelIndex&) const { return 0; }
-          QVariant data (const QModelIndex&, int) const { return QVariant(); }
-          void update_model ()
-          {
-            this->beginResetModel ();
-            this->endResetModel ();
-          }
-        };
-        ]], [[
-        item_model model;
-        model.update_model ();
-        ]])],
-      octave_cv_func_qabstractitemmodel_beginresetmodel=yes,
-      octave_cv_func_qabstractitemmodel_beginresetmodel=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qabstractitemmodel_beginresetmodel = yes; then
-    AC_DEFINE(HAVE_QABSTRACTITEMMODEL_BEGINRESETMODEL, 1,
-      [Define to 1 if you have the `QAbstractItemModel::beginResetModel' member function.])
-  fi
-])
-dnl
-dnl Check whether the Qt QComboBox class has the setCurrentText
-dnl function.  This function was introduced in Qt 5.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QCOMBOBOX_SETCURRENTTEXT], [
-  AC_CACHE_CHECK([for QComboBox::setCurrentText],
-    [octave_cv_func_qcombobox_setcurrenttext],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CPPFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QComboBox>
-        ]], [[
-        QComboBox combo_box (nullptr);
-        combo_box.setCurrentText ("text");
-        ]])],
-      octave_cv_func_qcombobox_setcurrenttext=yes,
-      octave_cv_func_qcombobox_setcurrenttext=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qcombobox_setcurrenttext = yes; then
-    AC_DEFINE(HAVE_QCOMBOBOX_SETCURRENTTEXT, 1,
-      [Define to 1 if you have the `QComboBox::setCurrentText' member function.])
-  fi
-])
-dnl
 dnl Check whether the Qt QGuiApplication class has the setDesktopFileName
 dnl static member function.  This function was introduced in Qt 5.7.
 dnl
@@ -411,99 +331,6 @@
   fi
 ])
 dnl
-dnl Check whether the Qt QHeaderView class has the setSectionResizeMode
-dnl function.  This function was introduced in Qt 5.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QHEADERVIEW_SETSECTIONRESIZEMODE], [
-  AC_CACHE_CHECK([for QHeaderView::setSectionResizeMode],
-    [octave_cv_func_qheaderview_setsectionresizemode],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CPPFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QHeaderView>
-        ]], [[
-        QHeaderView header_view (Qt::Horizontal);
-        header_view.setSectionResizeMode (QHeaderView::Interactive);
-        ]])],
-      octave_cv_func_qheaderview_setsectionresizemode=yes,
-      octave_cv_func_qheaderview_setsectionresizemode=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qheaderview_setsectionresizemode = yes; then
-    AC_DEFINE(HAVE_QHEADERVIEW_SETSECTIONRESIZEMODE, 1,
-      [Define to 1 if you have the `QHeaderView::setSectionResizeMode' member function.])
-  fi
-])
-dnl
-dnl Check whether the Qt QHeaderView class has the setSectionsClickable
-dnl function.  This function was introduced in Qt 5.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QHEADERVIEW_SETSECTIONSCLICKABLE], [
-  AC_CACHE_CHECK([for QHeaderView::setSectionsClickable],
-    [octave_cv_func_qheaderview_setsectionsclickable],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CPPFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QHeaderView>
-        ]], [[
-        QHeaderView header_view (Qt::Horizontal);
-        header_view.setSectionsClickable (true);
-        ]])],
-      octave_cv_func_qheaderview_setsectionsclickable=yes,
-      octave_cv_func_qheaderview_setsectionsclickable=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qheaderview_setsectionsclickable = yes; then
-    AC_DEFINE(HAVE_QHEADERVIEW_SETSECTIONSCLICKABLE, 1,
-      [Define to 1 if you have the `QHeaderView::setSectionsClickable' member function.])
-  fi
-])
-dnl
-dnl Check whether the Qt QHeaderView class has the setSectionsMovable
-dnl function.  This function was introduced in Qt 5.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QHEADERVIEW_SETSECTIONSMOVABLE], [
-  AC_CACHE_CHECK([for QHeaderView::setSectionsMovable],
-    [octave_cv_func_qheaderview_setsectionsmovable],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CPPFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QHeaderView>
-        ]], [[
-        QHeaderView header_view (Qt::Horizontal);
-        header_view.setSectionsMovable (true);
-        ]])],
-      octave_cv_func_qheaderview_setsectionsmovable=yes,
-      octave_cv_func_qheaderview_setsectionsmovable=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qheaderview_setsectionsmovable = yes; then
-    AC_DEFINE(HAVE_QHEADERVIEW_SETSECTIONSMOVABLE, 1,
-      [Define to 1 if you have the `QHeaderView::setSectionsMovable' member function.])
-  fi
-])
-dnl
 dnl Check whether the Qt QHelpSearchQueryWidget class has the searchInput
 dnl member function.  This function was introduced in Qt 5.9.
 dnl
@@ -536,133 +363,6 @@
   fi
 ])
 dnl
-dnl Check whether the Qt function qInstallMessageHandler is available.
-dnl This function was introduced in Qt 5.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QINSTALLMESSAGEHANDLER], [
-  AC_CACHE_CHECK([for qInstallMessageHandler],
-    [octave_cv_func_qinstallmessagehandler],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CPPFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QtGlobal>
-        ]], [[
-        qInstallMessageHandler (nullptr);
-        ]])],
-      octave_cv_func_qinstallmessagehandler=yes,
-      octave_cv_func_qinstallmessagehandler=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qinstallmessagehandler = yes; then
-    AC_DEFINE(HAVE_QINSTALLMESSAGEHANDLER, 1,
-      [Define to 1 if you have the `qInstallMessageHandler' function.])
-  fi
-])
-dnl
-dnl Check whether the Qt class QLineEdit has the setPlaceholderText member
-dnl function.  This member function was introduced in Qt 4.7.
-dnl
-dnl FIXME: Delete this entirely when we can safely assume that Qt 4.7 or later
-dnl is in use everywhere, or when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QLINEEDIT_SETPLACEHOLDERTEXT], [
-  AC_CACHE_CHECK([for QLineEdit::setPlaceholderText in <QLinedEdit>],
-    [octave_cv_func_qlineedit_setplaceholdertext],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CPPFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QLineEdit>
-        ]], [[
-        QLineEdit line_edit;
-        line_edit.setPlaceholderText ("placeholder text");
-        ]])],
-      octave_cv_func_qlineedit_setplaceholdertext=yes,
-      octave_cv_func_qlineedit_setplaceholdertext=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qlineedit_setplaceholdertext = yes; then
-    AC_DEFINE(HAVE_QLINEEDIT_SETPLACEHOLDERTEXT, 1,
-      [Define to 1 if you have the `QLineEdit::setPlaceholderText' member function.])
-  fi
-])
-dnl
-dnl Check whether the Qt QMouseEvent class has the localPos function.
-dnl This function was introduced in Qt 5.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QMOUSEEVENT_LOCALPOS], [
-  AC_CACHE_CHECK([for QMouseEvent::localPos],
-    [octave_cv_func_qmouseevent_localpos],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CPPFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QMouseEvent>
-        ]], [[
-        QMouseEvent *event;
-        event->localPos ();
-        ]])],
-      octave_cv_func_qmouseevent_localpos=yes,
-      octave_cv_func_qmouseevent_localpos=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qmouseevent_localpos = yes; then
-    AC_DEFINE(HAVE_QMOUSEEVENT_LOCALPOS, 1,
-      [Define to 1 if you have the `QMouseEvent::localPos' member function.])
-  fi
-])
-dnl
-dnl Check whether QObject::findChildren accepts Qt::FindChildOptions
-dnl argument.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QOBJECT_FINDCHILDREN_ACCEPTS_FINDCHILDOPTIONS], [
-  AC_CACHE_CHECK([whether QObject::findChildren accepts Qt::FindChildOptions],
-    [octave_cv_func_qobject_findchildren_accepts_findchildoptions],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CXXFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QList>
-        #include <QObject>
-        #include <QWidget>
-        ]], [[
-        QObject obj;
-        QList<QWidget *> widgets
-          = obj.findChildren<QWidget *> ("name", Qt::FindDirectChildrenOnly);
-        ]])],
-      octave_cv_func_qobject_findchildren_accepts_findchildoptions=yes,
-      octave_cv_func_qobject_findchildren_accepts_findchildoptions=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qobject_findchildren_accepts_findchildoptions = yes; then
-    AC_DEFINE(QOBJECT_FINDCHILDREN_ACCEPTS_FINDCHILDOPTIONS, 1,
-      [Define to 1 if 'QObject::findChildren' accepts 'Qt::FindChildOptions' argument.])
-  fi
-])
-dnl
 dnl Check whether the Qt class QScreen has the devicePixelRatio member function.
 dnl This member function was introduced in Qt 5.5.
 dnl
@@ -693,112 +393,6 @@
   fi
 ])
 dnl
-dnl Check whether the Qt class QTabWidget has the setMovable member function.
-dnl This member function was introduced in Qt 4.5.
-dnl
-dnl FIXME: Delete this entirely when we can safely assume that Qt 4.5 or later
-dnl is in use everywhere, or when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QTABWIDGET_SETMOVABLE], [
-  AC_CACHE_CHECK([for QTabWidget::setMovable in <QTabWidget>],
-    [octave_cv_func_qtabwidget_setmovable],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CXXFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QTabWidget>
-        class tab_widget : public QTabWidget
-        {
-        public:
-          tab_widget (QWidget *parent = 0) : QTabWidget (parent) { this->setMovable (true); }
-          ~tab_widget () {}
-        };
-        ]], [[
-        tab_widget tw;
-        ]])],
-      octave_cv_func_qtabwidget_setmovable=yes,
-      octave_cv_func_qtabwidget_setmovable=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qtabwidget_setmovable = yes; then
-    AC_DEFINE(HAVE_QTABWIDGET_SETMOVABLE, 1,
-      [Define to 1 if you have the `QTabWidget::setMovable' member function.])
-  fi
-])
-dnl
-dnl Check whether the Qt class QWheelEvent has the angleDelta member function.
-dnl This member function was introduced in Qt 5.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QWHEELEVENT_ANGLEDELTA], [
-  AC_CACHE_CHECK([for QWheelEvent::angleDelta in <QWheelEvent>],
-    [octave_cv_func_qwheelevent_angledelta],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CXXFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QWheelEvent>
-        class wheel_event : public QWheelEvent
-        {
-        public:
-          wheel_event (QWidget *parent = 0) : QWheelEvent (parent) { this->angleDelta (); }
-          ~wheel_event () {}
-        };
-        ]], [[
-        wheel_event tw;
-        ]])],
-      octave_cv_func_qwheelevent_angledelta=yes,
-      octave_cv_func_qwheelevent_angledelta=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qwheelevent_angledelta = yes; then
-    AC_DEFINE(HAVE_QWHEELEVENT_ANGLEDELTA, 1,
-      [Define to 1 if you have the `QWheelEvent::angleDelta' member function.])
-  fi
-])
-dnl
-dnl Check whether Qt message handler function accepts QMessageLogContext
-dnl argument.  This change was introduced in Qt 5.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_FUNC_QTMESSAGEHANDLER_ACCEPTS_QMESSAGELOGCONTEXT], [
-  AC_CACHE_CHECK([whether Qt message handler accepts QMessageLogContext],
-    [octave_cv_func_qtmessagehandler_accepts_qmessagelogcontext],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CXXFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QtGlobal>
-        static void
-        msg_handler (QtMsgType, const QMessageLogContext &, const QString &)
-        { }
-        ]], [[
-        QtMessageHandler fptr = msg_handler;
-        ]])],
-      octave_cv_func_qtmessagehandler_accepts_qmessagelogcontext=yes,
-      octave_cv_func_qtmessagehandler_accepts_qmessagelogcontext=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_func_qtmessagehandler_accepts_qmessagelogcontext = yes; then
-    AC_DEFINE(QTMESSAGEHANDLER_ACCEPTS_QMESSAGELOGCONTEXT, 1,
-      [Define to 1 if Qt message handler accepts 'QMessageLogContext' argument.])
-  fi
-])
-dnl
 dnl Check whether HDF5 library has version 1.6 API functions.
 dnl
 AC_DEFUN([OCTAVE_CHECK_HDF5_HAS_VER_16_API], [
@@ -1580,68 +1174,6 @@
   AC_SUBST(TERM_LIBS)
 ])
 dnl
-dnl Check whether the Qt class QFont has the ForceIntegerMetrics enumerated
-dnl type member.  This property was introduced in Qt 4.7.
-dnl
-dnl FIXME: Delete this entirely when we can safely assume that Qt 4.7 or later
-dnl is in use everywhere, or when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_MEMBER_QFONT_FORCE_INTEGER_METRICS], [
-  AC_CACHE_CHECK([for QFont::ForceIntegerMetrics in <QFont>],
-    [octave_cv_decl_qfont_force_integer_metrics],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CXXFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QFont>
-        ]], [[
-        QFont::StyleStrategy strategy = QFont::ForceIntegerMetrics;
-        ]])],
-      octave_cv_decl_qfont_force_integer_metrics=yes,
-      octave_cv_decl_qfont_force_integer_metrics=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_decl_qfont_force_integer_metrics = yes; then
-    AC_DEFINE(HAVE_QFONT_FORCE_INTEGER_METRICS, 1,
-      [Define to 1 if `ForceIntegerMetrics' is a member of `QFont'.])
-  fi
-])
-dnl
-dnl Check whether the Qt class QFont has the Monospace enumerated type member.
-dnl This property was introduced in Qt 4.7.
-dnl
-dnl FIXME: Delete this entirely when we can safely assume that Qt 4.7 or later
-dnl is in use everywhere, or when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_CHECK_MEMBER_QFONT_MONOSPACE], [
-  AC_CACHE_CHECK([for QFont::Monospace in <QFont>],
-    [octave_cv_decl_qfont_monospace],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CXXFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QFont>
-        ]], [[
-        QFont::StyleHint hint = QFont::Monospace;
-        ]])],
-      octave_cv_decl_qfont_monospace=yes,
-      octave_cv_decl_qfont_monospace=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_decl_qfont_monospace = yes; then
-    AC_DEFINE(HAVE_QFONT_MONOSPACE, 1,
-      [Define to 1 if `Monospace' is a member of `QFont'.])
-  fi
-])
-dnl
 dnl Check for the Qhull version.
 dnl
 AC_DEFUN([OCTAVE_CHECK_QHULL_VERSION], [
@@ -1696,9 +1228,6 @@
 
   ## Check for Qt libraries
   case "$qt_version" in
-    4)
-      octave_qscintilla_libnames="qscintilla2-qt4 qscintilla2_qt4 qt4scintilla2 qscintilla2"
-    ;;
     5)
       octave_qscintilla_libnames="qscintilla2-qt5 qscintilla2_qt5 qt5scintilla2"
     ;;
@@ -1824,11 +1353,6 @@
 
   if test $build_qt_gui = yes; then
     BUILD_QT_SUMMARY_MSG="yes (version: $have_qt_version)"
-    if test x"$have_qt_version" = x4; then
-      AC_DEFINE(HAVE_QT4, 1, [Define to 1 if using Qt version 4.])
-      warn_qt_ver="Use of Qt version 4 is deprecated.  Support will be removed in Octave version 7."
-      OCTAVE_CONFIGURE_WARNING([warn_qt_ver])
-    fi
     if test x"$have_qt_version" = x5; then
       AC_DEFINE(HAVE_QT5, 1, [Define to 1 if using Qt version 5.])
     fi
@@ -2036,10 +1560,6 @@
 
   ## Check for Qt libraries
   case "$qt_version" in
-    4)
-      QT_OPENGL_MODULE="QtOpenGL"
-      QT_MODULES="QtCore QtGui QtNetwork QtHelp QtXml"
-    ;;
     5)
       QT_OPENGL_MODULE="Qt5OpenGL"
       QT_MODULES="Qt5Core Qt5Gui Qt5Network Qt5PrintSupport Qt5Help Qt5Xml"
@@ -2091,14 +1611,6 @@
         fi
       ;;
     esac
-
-    if test $qt_version = 4; then
-      ## Check for Qt4
-      if ! `$PKG_CONFIG --atleast-version=4.0.0 QtCore`; then
-        build_qt_gui=no
-        warn_qt_version="Qt >= 4.0.0 not found; disabling Qt GUI"
-      fi
-    fi
   fi
 
   QT_TOOLS_AVAILABLE=
@@ -2163,18 +1675,6 @@
   fi
 
   if test $build_qt_gui = yes; then
-    OCTAVE_CHECK_FUNC_QABSTRACTITEMMODEL_BEGINRESETMODEL
-
-    if test $octave_cv_func_qabstractitemmodel_beginresetmodel = no; then
-      build_qt_gui=no
-      warn_qt_abstract_item_model="QAbstractItemModel::beginResetModel not found; disabling Qt GUI"
-      ## Invalidate cache so that this test will be done again if we
-      ## perform the test with a different Qt version.
-      $as_unset octave_cv_func_qabstractitemmodel_beginresetmodel
-    fi
-  fi
-
-  if test $build_qt_gui = yes; then
     ## We have what we need to build the Qt GUI.  The remaining
     ## checks below are for optional features related to the Qt GUI.
 
@@ -2192,23 +1692,9 @@
     ## tests if they fail because we have already decided that the Qt
     ## version that we are testing now will be the one used.
 
-    OCTAVE_CHECK_FUNC_QCOMBOBOX_SETCURRENTTEXT
     OCTAVE_CHECK_FUNC_QGUIAPPLICATION_SETDESKTOPFILENAME
-    OCTAVE_CHECK_FUNC_QHEADERVIEW_SETSECTIONRESIZEMODE
-    OCTAVE_CHECK_FUNC_QHEADERVIEW_SETSECTIONSCLICKABLE
-    OCTAVE_CHECK_FUNC_QHEADERVIEW_SETSECTIONSMOVABLE
     OCTAVE_CHECK_FUNC_QHELPSEARCHQUERYWIDGET_SEARCHINPUT
-    OCTAVE_CHECK_FUNC_QINSTALLMESSAGEHANDLER
-    OCTAVE_CHECK_FUNC_QLINEEDIT_SETPLACEHOLDERTEXT
-    OCTAVE_CHECK_FUNC_QMOUSEEVENT_LOCALPOS
-    OCTAVE_CHECK_FUNC_QOBJECT_FINDCHILDREN_ACCEPTS_FINDCHILDOPTIONS
     OCTAVE_CHECK_FUNC_QSCREEN_DEVICEPIXELRATIO
-    OCTAVE_CHECK_FUNC_QTABWIDGET_SETMOVABLE
-    OCTAVE_CHECK_FUNC_QTMESSAGEHANDLER_ACCEPTS_QMESSAGELOGCONTEXT
-    OCTAVE_CHECK_FUNC_QWHEELEVENT_ANGLEDELTA
-    OCTAVE_CHECK_MEMBER_QFONT_FORCE_INTEGER_METRICS
-    OCTAVE_CHECK_MEMBER_QFONT_MONOSPACE
-    OCTAVE_HAVE_QGUIAPPLICATION
 
     if test -n "$OPENGL_LIBS"; then
       OCTAVE_CHECK_QT_OPENGL_OK([build_qt_graphics=yes],
@@ -2668,36 +2154,6 @@
   fi
 ])
 dnl
-dnl Check whether the Qt class QGuiApplication exists.
-dnl This class  was introduced in Qt 5.0.
-dnl
-dnl FIXME: Delete this entirely when we drop support for Qt 4.
-dnl
-AC_DEFUN([OCTAVE_HAVE_QGUIAPPLICATION], [
-  AC_CACHE_CHECK([for QGuiApplication],
-    [octave_cv_decl_qguiapplication],
-    [AC_LANG_PUSH(C++)
-    ac_octave_save_CPPFLAGS="$CPPFLAGS"
-    ac_octave_save_CXXFLAGS="$CXXFLAGS"
-    CPPFLAGS="$QT_CPPFLAGS $CXXPICFLAG $CPPFLAGS"
-    CXXFLAGS="$CXXPICFLAG $CXXFLAGS"
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-        #include <QGuiApplication>
-        ]], [[
-        QScreen *pscreen = QGuiApplication::primaryScreen ();
-        ]])],
-      octave_cv_decl_qguiapplication=yes,
-      octave_cv_decl_qguiapplication=no)
-    CPPFLAGS="$ac_octave_save_CPPFLAGS"
-    CXXFLAGS="$ac_octave_save_CXXFLAGS"
-    AC_LANG_POP(C++)
-  ])
-  if test $octave_cv_decl_qguiapplication = yes; then
-    AC_DEFINE(HAVE_QGUIAPPLICATION, 1,
-      [Define to 1 if `QGuiApplication' class is available.])
-  fi
-])
-dnl
 dnl Check for IEEE 754 data format.
 dnl
 AC_DEFUN([OCTAVE_IEEE754_DATA_FORMAT], [