In the first hunk we don't need a ‘executable-find’ call on
‘/gnu/store/…-direnv-…/bin/direnv’.

The second hunk is not good, because it will require to redefine both
direnv--detect and direnv--export in case user needs a custom direnv
binary.  direnv--export on upstream's master branch is different in way
we could avoid the second hunk.  Could you take a look on this?

Thanks,
Oleg.