'ghc-options: -j[N]' can make sense for specific user's setup, but it is not appropriate for a distributed package. Alternatively, if you want to use this, make it conditional based on a Cabal configuration flag (with 'manual: True' and 'default: False') and enable that flag during development. 'ghc-shared-options: -j[N]' can make sense for specific user's setup, but it is not appropriate for a distributed package. Alternatively, if you want to use this, make it conditional based on a Cabal configuration flag (with 'manual: True' and 'default: False') and enable that flag during development.