Install libghc-unix-compat-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libghc-unix-compat-doc
Description:
Haskell portable POSIX-compatible layer; documentation
This package provides portable Haskell implementations of some POSIX system calls contained in the unix package. This package re-exports the unix package when available. When it isn't available, portable implementations are used. . This package provides the documentation for a library for the Haskell programming language. See http://www.haskell.org/ for more information on Haskell.
Homepage: http://github.com/jystic/unix-compat
Version: 0.4.3.1-1
Section: universe/doc