diff --git a/pkgs/applications/networking/browsers/mozilla-plugins/mplayerplug-in/icecat3-idldir.patch b/pkgs/applications/networking/browsers/mozilla-plugins/mplayerplug-in/icecat3-idldir.patch
new file mode 100644
index 00000000000..39dbc7a3ed0
--- /dev/null
+++ b/pkgs/applications/networking/browsers/mozilla-plugins/mplayerplug-in/icecat3-idldir.patch
@@ -0,0 +1,16 @@
+We have to run `xpidl', but we need to provide it with the right IDL
+directory.  With GNU IceCat 3 (and possibly Firefox 3), this happens to be
+"$(pkg-config --variable=idldir libxul)/stable".
+
+--- mplayerplug-in-3.55/Makefile.in	2008-01-03 01:20:33.000000000 +0100
++++ mplayerplug-in-3.55/Makefile.in	2008-09-29 22:47:20.000000000 +0200
+@@ -46,7 +46,7 @@ datadir=@datadir@
+ LOCALEDIR=$(datadir)/locale
+ MOZILLA_HOME=@MOZILLA_HOME@
+ GECKO_XPIDL=@GECKO_XPIDL@
+-GECKO_IDLDIR=@GECKO_IDLDIR@
++GECKO_IDLDIR=@GECKO_IDLDIR@/stable
+ 
+ PIXMAPS=pixmaps/logo.xpm pixmaps/progress_left.xpm pixmaps/progress_right.xpm \
+ 	pixmaps/progress_fill.xpm pixmaps/progress_middle.xpm
+