Binaries using hlint have hlint_datadir hardcoded to build directory, not destroot

I’m trying to port IHaskell to MacPorts. IHaskell uses hlint.

The issue is that both stack and cabal builds create binaries that point to the build directory in .stack or .cabal-sandbox, not the install directory with prefix, say, /opt/local/bin. After the build, these temporary build directories are discarded, and neither ihaskell nor hlint binaries work.

I see that there is an hlint --datadir option:

https://github.com/ndmitchell/hlint/blob/c62b61696621cd5ebba408ec5bcc2fcdadb603cc/cc/Engine.hs#L65-L70

It seems like it should be straightforward, but I’m not sure how to build projects that use hlint to set its data directory to have prefix /opt/local so that destrooting the build will work.

Any pointers would be appreciated.

Related:

• https://github.com/macports/macports-ports/pull/4706
• https://github.com/gibiansky/IHaskell/issues/1061
• https://github.com/ndmitchell/hlint/issues/503

Start with cc/Engine.hs at the linked datadir handling and reproduce a stack or cabal build that installs outside its temporary build directory. Determine how the installed binary should locate its data directory; done means hlint and dependent IHaskell binaries continue working after .stack or .cabal-sandbox are removed and use the destroot prefix.