ghc-pkg should splice $topdir on Windows
On Windows, filepaths in the package database use
$topdir rather than including the absolute filesystem location, because the installation is independent of its final resting place. So we get things like this:
> ghc-pkg field base haddock-html haddock-html: $topdir\html\libraries\base
Unfortunately this means that Haddock's
--use-package flag doesn't work, because it can't figure out what
$topdir is. The solution would be to either
ghc-pkgsplice in the actual value of
do the Windows installation in the same way as the Unix installation,
package.confat install time.
The second option probably involves more work.