diff --git a/pkgs/development/libraries/celt/0.5.1.nix b/pkgs/development/libraries/celt/0.5.1.nix
index 561be1ba2819..e45d74345d44 100644
--- a/pkgs/development/libraries/celt/0.5.1.nix
+++ b/pkgs/development/libraries/celt/0.5.1.nix
@@ -7,4 +7,11 @@ callPackage ./generic.nix (args // rec{
     url = "http://downloads.xiph.org/releases/celt/celt-${version}.tar.gz";
     sha256 = "0bkam9z5vnrxpbxkkh9kw6yzjka9di56h11iijikdd1f71l5nbpw";
   };
+
+  # Don't build tests due to badness with ec_ilog
+  prePatch = ''
+    substituteInPlace Makefile.in \
+      --replace 'SUBDIRS = libcelt tests' \
+                'SUBDIRS = libcelt'
+  '';
 })
diff --git a/pkgs/development/libraries/celt/generic.nix b/pkgs/development/libraries/celt/generic.nix
index 4ab554561f73..9d861f2c4328 100644
--- a/pkgs/development/libraries/celt/generic.nix
+++ b/pkgs/development/libraries/celt/generic.nix
@@ -1,5 +1,6 @@
 { stdenv, version, src
 , liboggSupport ? true, libogg ? null # if disabled only the library will be built
+, prePatch ? ""
 , ...
 }:
 
@@ -10,6 +11,8 @@ stdenv.mkDerivation rec {
 
   inherit src;
 
+  inherit prePatch;
+
   buildInputs = []
     ++ stdenv.lib.optional liboggSupport libogg;