Crashes on clipboard operations

  http://mantis.freepascal.org/view.php?id=12396

--- lcl/interfaces/gtk/gtkwidgetset.inc
+++ lcl/interfaces/gtk/gtkwidgetset.inc
@@ -5055,11 +5055,16 @@
     while (CurSelList<>nil) do begin
       TargetSelList := CurSelList^.Data;
       gtk_target_list_unref(TargetSelList^.List);
+      {$ifndef gtk1}
+      if (gtk_major_version = 2) and (gtk_minor_version > 12) and (@g_slice_free1 <> nil) then
+        g_slice_free1(SizeOf(TGtkTargetSelectionList), TargetSelList)
+      else
+      {$endif}
       g_free(TargetSelList);
       CurSelList := CurSelList^.Next;
     end;
     g_list_free(SelectionLists);
-    gtk_object_set_data (PGtkObject(Widget),gtk_selection_handler_key,GtkNil);
+    gtk_object_set_data (PGtkObject(Widget), gtk_selection_handler_key, GtkNil);
     {$IFDEF DEBUG_CLIPBOARD}
     DebugLn('  ClearTargetLists WWW END');
     {$ENDIF}
--- lcl/interfaces/gtk/gtkextra.pp
+++ lcl/interfaces/gtk/gtkextra.pp
@@ -54,4 +54,11 @@
 {$I gtk2extra.inc}
 {$endif}
 
+{$ifdef gtk2}
+initialization
+  Initialize;
+finalization
+  Finalize;
+{$endif}
+
 end.
--- lcl/interfaces/gtk2/gtk2extra.inc
+++ lcl/interfaces/gtk2/gtk2extra.inc
@@ -53,3 +53,16 @@
 end;
 {$endif}
 
+procedure Initialize;
+begin
+  Pointer(g_slice_free1) := nil;
+  glibhandle := LoadLibrary(gliblib);
+  if glibhandle <> 0 then
+    Pointer(g_slice_free1) := GetProcAddress(glibhandle, 'g_slice_free1');
+end;
+
+procedure Finalize;
+begin
+  if glibhandle <> 0 then
+    FreeLibrary(glibhandle);
+end;
--- lcl/interfaces/gtk2/gtk2extrah.inc
+++ lcl/interfaces/gtk2/gtk2extrah.inc
@@ -23,7 +23,7 @@
   {$ifdef HasGdk2X}
   gdk2x,
   {$endif}
-  Pango;
+  Pango, dynlibs;
 
 const
   gdkdll = gdklib;
@@ -190,3 +190,6 @@
 {$ifdef GTK_2_10}
 function gdk_screen_is_composited(screen: PGdkScreen): gboolean; cdecl; external gdklib;
 {$endif}
+var
+  glibhandle: PtrUInt = 0;
+  g_slice_free1: procedure(block_size:gsize; mem_block:gpointer); cdecl;