[gimp] Remove use of custom marshallers in favor of GLib ones

[Jehan <jehanp src gnome org>]

commit 6892326e8e08f4b53f4c75652f5db9ad5d8abc4b
Author: Stanislav Grinkov <43956-stanislavgrinkov users noreply gitlab gnome org>
Date:   Fri Aug 6 12:34:30 2021 +0600

    Remove use of custom marshallers in favor of GLib ones

 libgimpwidgets/gimpcolordisplaystack.c | 3 +--
 libgimpwidgets/gimpcolorselector.c     | 3 +--
 libgimpwidgets/gimpwidgetsmarshal.list | 2 --
 3 files changed, 2 insertions(+), 6 deletions(-)
---
diff --git a/libgimpwidgets/gimpcolordisplaystack.c b/libgimpwidgets/gimpcolordisplaystack.c
index c3e3c9bddf..808423bcfc 100644
--- a/libgimpwidgets/gimpcolordisplaystack.c
+++ b/libgimpwidgets/gimpcolordisplaystack.c
@@ -109,8 +109,7 @@ gimp_color_display_stack_class_init (GimpColorDisplayStackClass *klass)
                   G_TYPE_FROM_CLASS (klass),
                   G_SIGNAL_RUN_FIRST,
                   G_STRUCT_OFFSET (GimpColorDisplayStackClass, removed),
-                  NULL, NULL,
-                  _gimp_widgets_marshal_VOID__OBJECT,
+                  NULL, NULL, NULL,
                   G_TYPE_NONE, 1,
                   GIMP_TYPE_COLOR_DISPLAY);
 
diff --git a/libgimpwidgets/gimpcolorselector.c b/libgimpwidgets/gimpcolorselector.c
index c03b01d7db..8b330fd550 100644
--- a/libgimpwidgets/gimpcolorselector.c
+++ b/libgimpwidgets/gimpcolorselector.c
@@ -100,8 +100,7 @@ gimp_color_selector_class_init (GimpColorSelectorClass *klass)
                   G_TYPE_FROM_CLASS (klass),
                   G_SIGNAL_RUN_FIRST,
                   G_STRUCT_OFFSET (GimpColorSelectorClass, channel_changed),
-                  NULL, NULL,
-                  _gimp_widgets_marshal_VOID__ENUM,
+                  NULL, NULL, NULL,
                   G_TYPE_NONE, 1,
                   GIMP_TYPE_COLOR_SELECTOR_CHANNEL);
 
diff --git a/libgimpwidgets/gimpwidgetsmarshal.list b/libgimpwidgets/gimpwidgetsmarshal.list
index b52f2baae2..d922a6d680 100644
--- a/libgimpwidgets/gimpwidgetsmarshal.list
+++ b/libgimpwidgets/gimpwidgetsmarshal.list
@@ -22,10 +22,8 @@
 #   NONE        deprecated alias for VOID
 #   BOOL        deprecated alias for BOOLEAN
 
-VOID: ENUM
 VOID: ENUM, BOOLEAN
 VOID: INT, INT 
-VOID: OBJECT
 VOID: OBJECT, INT
 VOID: BOXED, BOXED
 VOID: STRING, FLAGS