[gegl] bin: add ffi binding for mrg_forget_image

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 3f841f54a4de99291a97205a735393e20fcf0b3b
Author: Øyvind Kolås <pippin gimp org>
Date:   Fri Mar 1 11:33:25 2019 +0100

    bin: add ffi binding for mrg_forget_image

 bin/lua/init.lua | 1 +
 bin/lua/mrg.lua  | 3 +++
 2 files changed, 4 insertions(+)
---
diff --git a/bin/lua/init.lua b/bin/lua/init.lua
index fb6ee498d..e59272d3d 100644
--- a/bin/lua/init.lua
+++ b/bin/lua/init.lua
@@ -2,6 +2,7 @@
 ffi = require('ffi')
 lgi = require 'lgi'
 
+os      = require 'os'
 GLib    = lgi.GLib
 GObject = lgi.GObject
 Mrg     = require('mrg')
diff --git a/bin/lua/mrg.lua b/bin/lua/mrg.lua
index 8ab6d842d..b56410b26 100644
--- a/bin/lua/mrg.lua
+++ b/bin/lua/mrg.lua
@@ -148,6 +148,8 @@ MrgImage *mrg_query_image (Mrg *mrg, const char *path,
                            int *width,
                            int *height);
 
+void mrg_forget_image (Mrg *mrg, const char *path);
+
 /* built in http / local file URI fetcher, this is the callback interface
  * that needs to be implemented for mrg_xml_render if external resources (css
  * files / png images) are to be retrieved and rendered.
@@ -784,6 +786,7 @@ ffi.metatype('Mrg', {__index = {
     return rw[0], rh[0]
   end,
   image            = function (...) C.mrg_image(...) end,
+  forget_image     = function (...) C.mrg_forget_image(...) end,
   render_pdf       = function (...) C.mrg_render_pdf(...) end,
   render_svg       = function (...) C.mrg_render_svg(...) end,
   is_printing      = function (...) return C.mrg_is_printing (...) end,