Using nix native functions to retrieve derivation output paths
Using nix native functions to retrieve derivation output paths

This solves the need to include both `zlib.out` & `zlib.dev` or
`ncurses.out` & `ncurses.dev` in `packages:` in stack.yaml

Fuuzetsu/stack,juhp/stack,mrkkrp/stack,deech/stack,martin-kolinek/stack,AndreasPK/stack,AndrewRademacher/stack,deech/stack,Fuuzetsu/stack,anton-dessiatov/stack,MichielDerhaeg/stack,AndrewRademacher/stack,juhp/stack,Blaisorblade/stack,anton-dessiatov/stack,Blaisorblade/stack,martin-kolinek/stack,AndreasPK/stack,MichielDerhaeg/stack,mrkkrp/stack