[GHC] #10143: Separate PprFlags (used by Outputable) from DynFlags

[GHC]

#10143: Separate PprFlags (used by Outputable) from DynFlags
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        Reporter:  ezyang            |                Owner:  ezyang
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #10961            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by dalaing):

 It's not clear to me if this change is wanted or not.

 I was mostly after this to clean up how #10961 deals with messages and
 also to help break a circular dependency.

 Beyond that I was only looking for a behaviour preserving split out of
 `PprFlags` - even containing things not strictly related to pretty
 printing - in order to place an upper bound on what information can be
 reached while pretty printing.

 The idea was that a) it'll make people stop and think about other ways of
 accessing non-printing information while pretty printing, so hopefully
 things won't get any worse and b) we can open tickets to try to clean up
 the code that accesses the platform constants or general flags from the
 pretty printer, so that things get better over time.

 If folks think that's a lateral move / change for the sake of change / a
 step back, I'm happy to work on something else instead :)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10143#comment:14>
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