Error building Haskell for Pandoc

[Ralph Seichter]

I wanted to take a shot at updating the Pandoc port from version 1.12 to
2.7.1, but the GHC prerequisite build fails.

  :info:build deriveConstants: fd:31: hClose: invalid argument (Bad file descriptor)
  :info:build make[1]: *** [includes/dist-derivedconstants/header/DerivedConstants.h] Error 1

I found https://trac.macports.org/ticket/48899 but I am unsure if I
should add the build log file there or if a new ticket would be better?
I am also wondering about the chances of actually finding somebody
willing to work on Haskell, seeing that the existing ticket was filed
four years ago? Personally, I don't know enough about GHC.

-Ralph

P.S.: I know there is a Pandoc installer for macOS available, but it
looks like conversion to PDF does not work out of the box.