See 61c373c...6b83aed
The newly introduced commit (87e7cd7) adds support for LAMBDA_MOD_N_DIR_LEVELS
to control the amount of dir levels shown in the prompt.
This ensures that no impurity exists due to implicitly depending
on`/usr/bin/env`.
It stores the theme into `$out/share/zsh/themes` to make it possible to
find theme using `buildEnv` and remain consistent with other ZSH
extensions.