[GHC] #10536: Clear up how to turn off dynamic linking in build.mk

[GHC]

#10536: Clear up how to turn off dynamic linking in build.mk
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              Reporter:  thomie      |             Owner:
                  Type:  task        |            Status:  new
              Priority:  normal      |         Milestone:  7.12.1
             Component:  Build       |           Version:  7.10.1
  System                             |  Operating System:  Unknown/Multiple
              Keywords:              |   Type of failure:  None/Unknown
          Architecture:              |        Blocked By:
  Unknown/Multiple                   |   Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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 See https://mail.haskell.org/pipermail/ghc-devs/2014-December/007725.html

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10536>
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