[GHC] #13541: Make it easier to use the gold linker

[GHC]

#13541: Make it easier to use the gold linker
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        Reporter:  bgamari           |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13810            |  Differential Rev(s):  Phab:D3449
       Wiki Page:                    |
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Comment (by nh2):

 > The user can explicitly request one or the other by passing the LD=...
 variable to configure.

 @bgamari: To clarify, will GHC still at run-time detect which linker is
 available, and can the user still at run-time tell GHC which linker to
 use? At configure time, gold may not be installed, or it may be
 uninstalled afterwards, or the user maybe be using a bindist but for some
 reasons wants to force GHC to use `ld` or `gold` (for example, if `gold`
 doesn't work for them for some reason).

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13541#comment:20>
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