[GHC] #9970: Export more types in GHC.RTS.Flags

[GHC]

#9970: Export more types in GHC.RTS.Flags
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              Reporter:              |             Owner:
  RyanGlScott                        |            Status:  new
                  Type:  feature     |         Milestone:
  request                            |           Version:  7.10.1-rc1
              Priority:  normal      |  Operating System:  Unknown/Multiple
             Component:              |   Type of failure:  Other
  libraries/base                     |        Blocked By:
              Keywords:              |   Related Tickets:
          Architecture:              |
  Unknown/Multiple                   |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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 There are some ADTs in {{{GHC.RTS.Flags}}} that have arguments whose types
 are not exported. These types are:

 * {{{GiveGCStats}}} (found in {{{GCFlags}}})
 * {{{DoCostCentres}}} (found in {{{CCFlags}}})
 * {{{DoHeapProfile}}} (found in {{{ProfFlags}}})
 * {{{DoTrace}}} (found in {{{TraceFlags}}})

 This makes it pretty difficult to do anything useful with them, since they
 can't be pattern-matched.

 In addition, there are some unexported type synonyms:

 * {{{type Time = Word64}}}
 * {{{type Nat = #{type unsigned int} }}} (likely a {{{Word32}}})

 The Haddock docs for {{{GHC.RTS.Flags}}} don't give much of an indication
 of what {{{Time}}} and {{{Nat}}} are, and since they're already documented
 in
 [https://phabricator.haskell.org/diffusion/GHC/browse/master/libraries/base/GHC/RTS/Flags.hsc;0bef02e49fb2907989127d77ae61ed48ba87ae18$50-54
 the source], they should probably be exported.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9970>
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