[GHC] #3841: build for libffi assumes tar supports -z

[GHC]

#3841: build for libffi assumes tar supports -z
---------------------------------+------------------------------------------
    Reporter:  duncan            |       Owner:                     
        Type:  bug               |      Status:  new                
    Priority:  normal            |   Component:  Build System       
     Version:  6.12.1            |    Keywords:                     
          Os:  Solaris           |    Testcase:                     
Architecture:  Unknown/Multiple  |     Failure:  Building GHC failed
---------------------------------+------------------------------------------

Comment(by duncan):

 Spoke too soon, another instance in `libraries/integer-gmp/gmp/ghc.mk`
 {{{
 cd libraries/integer-gmp/gmp && $(TAR) -jxf ../../../$(GMP_TARBALL)
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3841#comment:1>
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