[GHC] #6063: GHC's build-time ld-flag checks are problematic

[GHC]

#6063: GHC's build-time ld-flag checks are problematic
---------------------------------+------------------------------------------
    Reporter:  parcs             |       Owner:  thoughtpolice          
        Type:  bug               |      Status:  patch                  
    Priority:  high              |   Milestone:  7.8.1                  
   Component:  Compiler          |     Version:  7.4.1                  
    Keywords:                    |          Os:  Linux                  
Architecture:  Unknown/Multiple  |     Failure:  GHC doesn't work at all
  Difficulty:  Unknown           |    Testcase:                         
   Blockedby:                    |    Blocking:                         
     Related:  #4862             |  
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Comment(by igloo):

 Generally looks fine to me. A few comments:

 Re this comment:
 {{{
 It can also simply happen
 by using a binary distribution: GHC was built on a machine using GNU ld,
 and installed on a machine using GNU gold.
 }}}
 if by "binary distribution" you mean the bindists that we have on the
 website, then that's not the case: The info is redetected when you install
 a bindist.

 On `compiler/main/SysTools.lhs` line 642, `case os of` doesn't actually
 match on the os at all AFAICS.

 In `--make` mode, do we sometimes link many times? Even if not, GHC API
 users might link many times. It might be better to put an `IORef (Maybe
 LinkerInfo)` in DynFlags, to cache the info.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6063#comment:16>
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