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

[GHC]

#11026: Bump `base` version to 4.9.0.0
-------------------------------------+-------------------------------------
        Reporter:  hvr               |                Owner:  hvr
            Type:  task              |               Status:  closed
        Priority:  highest           |            Milestone:  8.0.1
       Component:  libraries/base    |              Version:
      Resolution:  fixed             |             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:                    |
-------------------------------------+-------------------------------------
Changes (by hvr):

 * status:  new => closed
 * resolution:   => fixed


--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11026#comment:12>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler