[GHC] #9068: Don't uninstall signal handlers if none were installed

[GHC]

#9068: Don't uninstall signal handlers if none were installed
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        Reporter:  tomgr                        |            Owner:
            Type:  bug                          |  simonmar
        Priority:  normal                       |           Status:  new
       Component:  Runtime System               |        Milestone:
      Resolution:                               |          Version:  7.8.2
Operating System:  Windows                      |         Keywords:
 Type of failure:  Incorrect result at runtime  |     Architecture:
       Test Case:                               |  Unknown/Multiple
        Blocking:                               |       Difficulty:
                                                |  Unknown
                                                |       Blocked By:
                                                |  Related Tickets:
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Comment (by Simon Marlow <marlowsd@…>):

 In [changeset:"bc7d49a658a516679cc264502e72560c1d2c2314/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="bc7d49a658a516679cc264502e72560c1d2c2314"
 Only uninstall signal handlers if they were actually installed (#9068)

 Submitted by: tomgr
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9068#comment:1>
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