[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 bgamari):

 I've updated Phab:D3449 to reflect my current thinking on this. Namely, we
 provide a `configure` flag that indicates that the user doesn't mind if
 GHC overrides the system's default linker. If this flag is passed, we use
 either `gold` or `lld`, if available. The user can explicitly request one
 or the other by passing the `LD=...` variable to `configure`.

 Does this seem reasonable?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13541#comment:19>
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