diff --git a/pkgs/development/libraries/libtheora/default.nix b/pkgs/development/libraries/libtheora/default.nix
index 8514c299679..e846b213ee0 100644
--- a/pkgs/development/libraries/libtheora/default.nix
+++ b/pkgs/development/libraries/libtheora/default.nix
@@ -16,8 +16,8 @@ stdenv.mkDerivation ({
 }
 
 # It has an old config.guess that doesn't know the mips64el.
-// (if (stdenv.system == "mips64el-linux") then
+// stdenv.lib.optionalAttrs (stdenv.system == "mips64el-linux")
 {
   propagatedBuildInputs = [libogg libvorbis autoconf automake libtool];
   preConfigure = "rm config.guess; sh autogen.sh";
-} else {}))
+})