[GHC] #9713: Update comment about C helper for dynamic exports.

[GHC]

#9713: Update comment about C helper for dynamic exports.
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              Reporter:  int-e       |            Owner:
                  Type:  task        |           Status:  patch
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Easy (less than 1
       Type of failure:  Other       |  hour)
             Test Case:              |       Blocked By:
              Blocking:              |  Related Tickets:
Differential Revisions:              |
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Comment (by int-e):

 Replying to [comment:2 thomie]:
 * I prepared the patch before writing the ticket, but I've updated the
 commit message to include the Trac number and a reference to the original
 patch (from 2011).
 * The patch only updates comments (note that it is changing a latex style
 .lhs file), so there's nothing to test.
 * "approximately" - in reality, the code has to extract the result of the
 call, and the details of that depend on whether LLVM is used or not, and
 I'm not sure I understand all of them. Since the emphasis of the comment
 is the creation of adjustors, I think it's ok to gloss over that.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9713#comment:3>
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