[GHC] #937: ghc-pkg should splice $topdir on Windows

[GHC]

#937: ghc-pkg should splice $topdir on Windows
--------------------------+-------------------------------------------------
  Reporter:  simonmar     |          Owner:          
      Type:  bug          |         Status:  new     
  Priority:  normal       |      Milestone:  6.6.1   
 Component:  Compiler     |        Version:  6.6     
  Severity:  normal       |       Keywords:          
Difficulty:  Easy (1 hr)  |   Architecture:  Multiple
        Os:  Windows      |  
--------------------------+-------------------------------------------------
On Windows, filepaths in the package database use `$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

  * have `ghc-pkg` splice in the actual value of `$topdir`, or

  * do the Windows installation in the same way as the Unix installation,
    and replace `$topdir` in `package.conf` at install time.

 The second option probably involves more work.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/937>
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