Revert "Merge pull request #555 from errge/master"

This reverts commit 8f7cfc0c7370e2b46a7692cc953ff7a43411d5d6, reversing
changes made to cc85ad4b1c365533049ec4af7adee0fe7c83c7b8.

The merge changed stdenv (a bit surprisingly, see #555 for details).