[GHC] #7375: Building ghc fails because it is looking for an old version of libgmp

[GHC]

#7375: Building ghc fails because it is looking for an old version of libgmp
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  Reporter:  mimosa               |          Owner:                  
      Type:  bug                  |         Status:  closed          
  Priority:  normal               |      Milestone:                  
 Component:  Compiler             |        Version:  7.4.2           
Resolution:  fixed                |       Keywords:                  
        Os:  Linux                |   Architecture:  Unknown/Multiple
   Failure:  Building GHC failed  |     Difficulty:  Unknown         
  Testcase:                       |      Blockedby:                  
  Blocking:                       |        Related:  5743            
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Comment(by simonmar):

 As long as `libgmp.so` doesn't point to `libgmp.so.3`, the GHC build
 should not depend on `libgmp.so.3`.

 Some background here: GHC is written in Haskell and therefore needs a
 working GHC to build it.  We call this the "stage 0" compiler, which is
 used to build a "stage 1" compiler, which finally builds the "stage 2"
 compiler, and the stage 2 is what we install.

 Now, in your case probably the stage 0 compiler you're using was built
 against `libgmp.so.3`, so you need that on your system to run it.
 Furthermore, stage 1 will also depend on `libgmp.so.3` because it was
 built by stage 0.  But stage 2 should not depend on `libgmp.so.3`, it
 should depend on whatever version is linked to from `libgmp.so` on your
 system (but you do need to have a `libgmp.so` somewhere, otherwise GHC
 will build its own `libgmp` and use that).

 GHCi won't even start up if you don't have the right `libgmp` installed,
 since the binary itself depends on it.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7375#comment:6>
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