[GHC] #12998: libraries/base/System/Posix/Types.hs: tries to define Floating instance for opaque type

[GHC]

#12998: libraries/base/System/Posix/Types.hs: tries to define Floating instance for
opaque type
-------------------------------------+-------------------------------------
        Reporter:  slyfox            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #12795            |  Differential Rev(s):  Phab:D2876,
       Wiki Page:                    |  Phab:D2952
-------------------------------------+-------------------------------------
Changes (by RyanGlScott):

 * differential:  Phab:D2876 => Phab:D2876, Phab:D2952


Comment:

 Since I was morbidly curious, I decided to see how much effort it would
 take to tweak the autoconf scripts to support detecting pointer types. To
 my surprise, it wasn't bad at all!

 I've opened to Phab:D2952 to add `CTimer` back to `System.Posix.Types`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12998#comment:9>
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