diff --git a/pkgs/applications/editors/emacs-modes/proofgeneral/default.nix b/pkgs/applications/editors/emacs-modes/proofgeneral/default.nix
index d8316886c34e..ce01d4b92046 100644
--- a/pkgs/applications/editors/emacs-modes/proofgeneral/default.nix
+++ b/pkgs/applications/editors/emacs-modes/proofgeneral/default.nix
@@ -1,25 +1,20 @@
 { stdenv, fetchurl, emacs, texinfo, texLive, perl, which, automake }:
 
-let
-  pname = "ProofGeneral";
-  version = "3.7.1.1";
-  name = "${pname}-${version}";
-  website = "http://proofgeneral.inf.ed.ac.uk";
-in
-
-stdenv.mkDerivation {
-  inherit name;
+stdenv.mkDerivation (rec {
+  name = "ProofGeneral-4.0";
 
   src = fetchurl {
-    url = "http://www.cl.cam.ac.uk/research/hvg/Isabelle/dist/contrib/${name}.tar.gz";
-    sha256 = "ae430590d6763618df50a662a37f0627d3c3c8f31372f6f0bb2116b738fc92d8";
+    url = http://proofgeneral.inf.ed.ac.uk/releases/ProofGeneral-4.0.tgz;
+    sha256 = "1ang2lsc97vl70fkgypfsr1ivdzsdliq3bkvympj30wnc7ayzbmq";
   };
 
   sourceRoot = name;
 
   buildInputs = [ emacs texinfo texLive perl which ];
 
-  patchPhase =
+  patches = [ ./emacs-23.3.patch ];
+
+  postPatch =
     '' sed -i "Makefile" \
            -e "s|^\(\(DEST_\)\?PREFIX\)=.*$|\1=$out|g ; \
                s|/sbin/install-info|install-info|g"
@@ -27,6 +22,8 @@ stdenv.mkDerivation {
        sed -i "bin/proofgeneral" -e's/which/type -p/g'
     '';
 
+  preBuild = "make clean";
+
   installPhase =
     # Copy `texinfo.tex' in the right place so that `texi2pdf' works.
     '' cp -v "${automake}/share/"automake-*/texinfo.tex doc
@@ -39,8 +36,8 @@ stdenv.mkDerivation {
       Proof General is a generic front-end for proof assistants (also known as
       interactive theorem provers), based on the customizable text editor Emacs.
     '';
-    homepage = website;
+    homepage = http://proofgeneral.inf.ed.ac.uk;
     license = "GPLv2+";
     platforms = stdenv.lib.platforms.gnu;  # arbitrary choice
   };
-}
+})
diff --git a/pkgs/applications/editors/emacs-modes/proofgeneral/emacs-23.3.patch b/pkgs/applications/editors/emacs-modes/proofgeneral/emacs-23.3.patch
new file mode 100644
index 000000000000..9bbc21a82b84
--- /dev/null
+++ b/pkgs/applications/editors/emacs-modes/proofgeneral/emacs-23.3.patch
@@ -0,0 +1,45 @@
+diff -Nuar ProofGeneral-4.0/contrib/mmm/mmm-mode.el ProofGeneral-4.0-nix/contrib/mmm/mmm-mode.el
+--- ProofGeneral-4.0/contrib/mmm/mmm-mode.el	2010-10-11 00:56:57.000000000 +0200
++++ ProofGeneral-4.0-nix/contrib/mmm/mmm-mode.el	2011-05-14 21:55:12.000000000 +0200
+@@ -160,9 +160,9 @@
+      (mmm-add-hooks)
+      (mmm-fixup-skeleton)
+      (make-local-variable 'font-lock-fontify-region-function)
+-     (make-local-variable 'font-lock-beginning-of-syntax-function)
++     (make-local-variable 'syntax-begin-function)
+      (setq font-lock-fontify-region-function 'mmm-fontify-region
+-	   font-lock-beginning-of-syntax-function 'mmm-beginning-of-syntax)
++	   syntax-begin-function 'mmm-beginning-of-syntax)
+      (setq mmm-mode t)
+      (condition-case err
+ 	 (mmm-apply-all)
+@@ -190,7 +190,7 @@
+     (mmm-update-submode-region)
+     (setq font-lock-fontify-region-function
+ 	  (get mmm-primary-mode 'mmm-fontify-region-function)
+-	  font-lock-beginning-of-syntax-function
++	  syntax-begin-function
+ 	  (get mmm-primary-mode 'mmm-beginning-of-syntax-function))
+     (mmm-update-font-lock-buffer)
+     (mmm-refontify-maybe)
+diff -Nuar ProofGeneral-4.0/contrib/mmm/mmm-region.el ProofGeneral-4.0-nix/contrib/mmm/mmm-region.el
+--- ProofGeneral-4.0/contrib/mmm/mmm-region.el	2010-10-11 00:56:57.000000000 +0200
++++ ProofGeneral-4.0-nix/contrib/mmm/mmm-region.el	2011-05-14 21:58:01.000000000 +0200
+@@ -548,7 +548,7 @@
+ 	    (put mode 'mmm-fontify-region-function
+ 		 font-lock-fontify-region-function))
+ 	  (put mode 'mmm-beginning-of-syntax-function
+-	       font-lock-beginning-of-syntax-function))
++	       syntax-begin-function))
+ 	;; Get variables
+ 	(setq global-vars (mmm-get-locals 'global)
+ 	      buffer-vars (mmm-get-locals 'buffer)
+@@ -768,7 +768,7 @@
+   ;; For some reason `font-lock-fontify-block' binds this to nil, thus
+   ;; preventing `mmm-beginning-of-syntax' from doing The Right Thing.
+   ;; I don't know why it does this, but let's undo it here.
+-  (let ((font-lock-beginning-of-syntax-function 'mmm-beginning-of-syntax))
++  (let ((syntax-begin-function 'mmm-beginning-of-syntax))
+     (mapc #'(lambda (elt)
+ 		(when (get (car elt) 'mmm-font-lock-mode)
+ 		  (mmm-fontify-region-list (car elt) (cdr elt))))