It turns out that the build of the nested_dict module requires the

distribute module to be already installed. This only showed up while
trying to build the AthenaDerivation release using Ninja. With
Makefiles just by chance the installation order was always correct
so far.

External/AtlasPyFwdBwdPorts/CMakeLists.txt

@@ -171,7 +171,8 @@ _setup_python_package( keyring
 # Install nested_dict:
 #_setup_python_package( nested_dict
 #   ${CMAKE_CURRENT_SOURCE_DIR}/src/nested_dict-1.0.9.tar.gz 
-#   aeb571306af08142d11fee99ff569019 )
+#   aeb571306af08142d11fee99ff569019 
+#   DEPENDS distribute )
 
 # Install ordereddict:
 _setup_python_package( ordereddict