[GHC] #11026: Bump `base` version to 4.9.0.0

[GHC]

#11026: Bump `base` version to 4.9.0.0
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        Reporter:  hvr               |                Owner:  hvr
            Type:  task              |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  libraries/base    |              Version:
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Herbert Valerio Riedel <hvr@…>):

 In [changeset:"f8ba4b55cc3a061458f5cfabf17de96128defbbb/ghc"
 f8ba4b55/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="f8ba4b55cc3a061458f5cfabf17de96128defbbb"
 Bump `base` version to 4.9.0.0 (closes #11026)

 This also relaxes a few upper bounds on base in the ghc.git repo;

 This required a mass-rewrite in testsuite/

   sed -i s,base-4.8.2.0,base-4.9.0.0,g $(git grep -Fl 'base-4.8.2.0')

 because it turns out the testsuite is still sensitive to package version
 changes.
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11026#comment:11>
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