python2Packages: default to dontUsePythonRecompileBytecode = true;

pkgs/development/interpreters/python/mk-python-derivation.nix

@@ -165,6 +165,11 @@ let
   # Python packages built through cross-compilation are always for the host platform.
   disallowedReferences = lib.optionals (python.stdenv.hostPlatform != python.stdenv.buildPlatform) [ python.pythonForBuild ];
 
+  # many packages that support python2, may include code
+  # which python2 is not able to compile
+  # mkDerivation hash will not change when passed null attrs
+  dontUsePythonRecompileBytecode = attrs.dontUsePythonRecompileBytecode or (if python.isPy27 then true else null);
+
   meta = {
     # default to python's platforms
     platforms = python.meta.platforms;