Handle deprecation of gtk_menu_popup

GTK+ 3.22 deprecates gtk_menu_popup in favour of various
gtk_menu_popup_at_* functions.  gtk_menu_popup_at_pointer seems most
appropriate, but that requires being able to pass it a GdkEvent rather
than just some elements of it.  In order to achieve that, I've
rearranged the scroll_event shim to construct a real GdkEventButton and
pass that down to button_internal.

unix/gtkwin.c

@@ -1817,56 +1817,58 @@ gboolean scroll_internal(struct gui_data *inst, gdouble delta, guint state,
 }
 #endif
 
-gboolean button_internal(struct gui_data *inst, guint32 timestamp,
-			 GdkEventType type, guint ebutton, guint state,
-			 gdouble ex, gdouble ey)
+static gboolean button_internal(struct gui_data *inst, GdkEventButton *event)
 {
     int shift, ctrl, alt, x, y, button, act, raw_mouse_mode;
 
     /* Remember the timestamp. */
-    inst->input_event_time = timestamp;
+    inst->input_event_time = event->time;
 
     show_mouseptr(inst, 1);
 
-    shift = state & GDK_SHIFT_MASK;
-    ctrl = state & GDK_CONTROL_MASK;
-    alt = state & inst->meta_mod_mask;
+    shift = event->state & GDK_SHIFT_MASK;
+    ctrl = event->state & GDK_CONTROL_MASK;
+    alt = event->state & inst->meta_mod_mask;
 
     raw_mouse_mode =
         send_raw_mouse && !(shift && conf_get_int(inst->conf,
                                                   CONF_mouse_override));
 
     if (!raw_mouse_mode) {
-        if (ebutton == 4 && type == GDK_BUTTON_PRESS) {
+        if (event->button == 4 && event->type == GDK_BUTTON_PRESS) {
             term_scroll(inst->term, 0, -SCROLL_INCREMENT_LINES);
             return TRUE;
         }
-        if (ebutton == 5 && type == GDK_BUTTON_PRESS) {
+        if (event->button == 5 && event->type == GDK_BUTTON_PRESS) {
             term_scroll(inst->term, 0, +SCROLL_INCREMENT_LINES);
             return TRUE;
         }
     }
 
-    if (ebutton == 3 && ctrl) {
+    if (event->button == 3 && ctrl) {
+#if GTK_CHECK_VERSION(3,22,0)
+	gtk_menu_popup_at_pointer(GTK_MENU(inst->menu), (GdkEvent *)event);
+#else
 	gtk_menu_popup(GTK_MENU(inst->menu), NULL, NULL, NULL, NULL,
-		       ebutton, timestamp);
+		       event->button, event->time);
+#endif
 	return TRUE;
     }
 
-    if (ebutton == 1)
+    if (event->button == 1)
 	button = MBT_LEFT;
-    else if (ebutton == 2)
+    else if (event->button == 2)
 	button = MBT_MIDDLE;
-    else if (ebutton == 3)
+    else if (event->button == 3)
 	button = MBT_RIGHT;
-    else if (ebutton == 4)
+    else if (event->button == 4)
 	button = MBT_WHEEL_UP;
-    else if (ebutton == 5)
+    else if (event->button == 5)
 	button = MBT_WHEEL_DOWN;
     else
 	return FALSE;		       /* don't even know what button! */
 
-    switch (type) {
+    switch (event->type) {
       case GDK_BUTTON_PRESS: act = MA_CLICK; break;
       case GDK_BUTTON_RELEASE: act = MA_RELEASE; break;
       case GDK_2BUTTON_PRESS: act = MA_2CLK; break;
@@ -1877,8 +1879,8 @@ gboolean button_internal(struct gui_data *inst, guint32 timestamp,
     if (raw_mouse_mode && act != MA_CLICK && act != MA_RELEASE)
 	return TRUE;		       /* we ignore these in raw mouse mode */
 
-    x = (ex - inst->window_border) / inst->font_width;
-    y = (ey - inst->window_border) / inst->font_height;
+    x = (event->x - inst->window_border) / inst->font_width;
+    y = (event->y - inst->window_border) / inst->font_height;
 
     term_mouse(inst->term, button, translate_button(button), act,
 	       x, y, shift, ctrl, alt);
@@ -1889,8 +1891,7 @@ gboolean button_internal(struct gui_data *inst, guint32 timestamp,
 gboolean button_event(GtkWidget *widget, GdkEventButton *event, gpointer data)
 {
     struct gui_data *inst = (struct gui_data *)data;
-    return button_internal(inst, event->time, event->type, event->button,
-			   event->state, event->x, event->y);
+    return button_internal(inst, event);
 }
 
 #if GTK_CHECK_VERSION(2,0,0)
@@ -1911,15 +1912,31 @@ gboolean scroll_event(GtkWidget *widget, GdkEventScroll *event, gpointer data)
         return FALSE;
 #else
     guint button;
+    GdkEventButton *event_button;
+    gboolean ret;
+
     if (event->direction == GDK_SCROLL_UP)
 	button = 4;
     else if (event->direction == GDK_SCROLL_DOWN)
 	button = 5;
     else
 	return FALSE;
 
-    return button_internal(inst, event->time, GDK_BUTTON_PRESS,
-			   button, event->state, event->x, event->y);
+    event_button = (GdkEventButton *)gdk_event_new(GDK_BUTTON_PRESS);
+    event_button->window = event->window;
+    event_button->send_event = event->send_event;
+    event_button->time = event->time;
+    event_button->x = event->x;
+    event_button->y = event->y;
+    event_button->axes = NULL;
+    event_button->state = event->state;
+    event_button->button = button;
+    event_button->device = event->device;
+    event_button->x_root = event->x_root;
+    event_button->y_root = event->y_root;
+    ret = button_internal(inst, event_button);
+    gdk_event_free(event_button);
+    return ret;
 #endif
 }
 #endif