[GHC] #916: windows installer should play nice with other Haskell tools

[GHC]

#916: windows installer should play nice with other Haskell tools
----------------------------------------+-----------------------------------
    Reporter:  claus.reinke@…           |        Owner:  neil                      
        Type:  bug                      |       Status:  patch                     
    Priority:  low                      |    Milestone:  _|_                       
   Component:  Build System             |      Version:  6.4.2                     
    Keywords:                           |     Testcase:  N/A                       
   Blockedby:                           |   Difficulty:  Moderate (less than a day)
          Os:  Windows                  |     Blocking:                            
Architecture:  Unknown/Multiple         |      Failure:  None/Unknown              
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Changes (by claus):

  * status:  new => patch
  * failure:  => None/Unknown


Comment:

 Ran into this yet again when trying out 7.0 and 7.1 snapshots. This has
 been delayed for so long now that I took a look and would like to suggest
 some changes. These changes do not address all points in this ticket, but:

 - add link to inno setup docs, so readers don't have to guess what ghc.iss
 might be

 - add `Task` section, and associated most Registry actions with separate
 (sub)tasks, so that file associations, default action, and `PATH` setting
 can be optional

 - copy license file into `doc` directory

 - install icon file again, so that `DefaultIcon` is no longer a dangling
 pointer (#4352)

 - only delete `ghc_haskell` key if empty (in case there were other tools
 using it)

 - add versioned `GHCi` to right-click menu (to allow for multiple tool
 installs)

 As I have zero experience with installer builders, you'll need to review.
 I suggest to review the modified `ghc.iss.in`, apply to HEAD and STABLE,
 then leave this ticket open for the remaining issues (such as claiming
 `.hs` for `ghc_haskell`).

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/916#comment:15>
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