diff --git a/pkgs/development/libraries/aterm/2.5.nix b/pkgs/development/libraries/aterm/2.5.nix
index bb9d3e0423e..097d616d988 100644
--- a/pkgs/development/libraries/aterm/2.5.nix
+++ b/pkgs/development/libraries/aterm/2.5.nix
@@ -11,6 +11,10 @@ stdenv.mkDerivation {
   patches = [
     # Fix for http://bugzilla.sen.cwi.nl:8080/show_bug.cgi?id=841
     ./max-long.patch
+
+    # Patch the ATerm header files so that they don't rely on
+    # SIZEOF_LONG, SIZEOF_INT and SIZEOF_VOID_P being set.
+    ./sizeof.patch
   ];
   
   doCheck = true;
diff --git a/pkgs/development/libraries/aterm/sizeof.patch b/pkgs/development/libraries/aterm/sizeof.patch
new file mode 100644
index 00000000000..2649cc56491
--- /dev/null
+++ b/pkgs/development/libraries/aterm/sizeof.patch
@@ -0,0 +1,56 @@
+diff -rc -x '*~' aterm-2.5-orig/aterm/aterm.c aterm-2.5/aterm/aterm.c
+*** aterm-2.5-orig/aterm/aterm.c	2007-02-27 23:41:31.000000000 +0100
+--- aterm-2.5/aterm/aterm.c	2010-02-23 15:10:38.000000000 +0100
+***************
+*** 150,155 ****
+--- 150,157 ----
+    if (initialized)
+      return;
+  
++   assert(sizeof(long) == sizeof(void *));
++ 
+    /*{{{  Handle arguments */
+  
+    for (lcv=1; lcv < argc; lcv++) {
+diff -rc -x '*~' aterm-2.5-orig/aterm/encoding.h aterm-2.5/aterm/encoding.h
+*** aterm-2.5-orig/aterm/encoding.h	2007-02-27 23:41:31.000000000 +0100
+--- aterm-2.5/aterm/encoding.h	2010-02-23 15:36:05.000000000 +0100
+***************
+*** 10,24 ****
+  {
+  #endif/* __cplusplus */
+  
+! #if SIZEOF_LONG > 4
+! #define AT_64BIT
+  #endif
+  
+! #if SIZEOF_LONG != SIZEOF_VOID_P
+! #error Size of long is not the same as the size of a pointer
+  #endif
+  
+! #if SIZEOF_INT > 4
+  #error Size of int is not 32 bits
+  #endif
+  
+--- 10,30 ----
+  {
+  #endif/* __cplusplus */
+  
+! #include <limits.h>
+! 
+! #ifndef SIZEOF_LONG
+! #if ULONG_MAX > 4294967295
+! #define SIZEOF_LONG 8
+! #else
+! #define SIZEOF_LONG 4
+! #endif
+  #endif
+  
+! #if SIZEOF_LONG > 4
+! #define AT_64BIT
+  #endif
+  
+! #if UINT_MAX > 4294967295
+  #error Size of int is not 32 bits
+  #endif
+