[GHC] #5743: Configurably use system-provided libffi

[GHC]

#5743: Configurably use system-provided libffi
------------------------------+---------------------------------------------
  Reporter:  nomeata          |          Owner:                  
      Type:  feature request  |         Status:  new             
  Priority:  normal           |      Milestone:  7.6.2           
 Component:  Build System     |        Version:  7.2.1           
Resolution:                   |       Keywords:                  
        Os:  Linux            |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown     |     Difficulty:  Unknown         
  Testcase:                   |      Blockedby:                  
  Blocking:                   |        Related:  #4496           
------------------------------+---------------------------------------------
Changes (by trommler):

  * owner:  trommler =>
  * status:  closed => new
  * resolution:  fixed =>


Comment:

 Replying to [comment:15 PHO]:
 > Your patch mentions a variable `LIBFFI_LIBS`, which isn't defined
 anywhere. I think you need something like:

 This was part of my original patch but did not make it into the above
 commit:
 {{{
 ifneq "$(UseSystemLibFFI)" "YES"
 LIBFFI_LIBS = -Lrts/dist/build -lffi
 else
 LIBFFI_LIBS =
 endif
 }}}
 In the case of {{{UseSystemLibFFI=="YES"}}} the correct linker flags will
 be set as part of {{{rts/libs.depend}}}, hence the empty definition for
 {{{LIBFFI_LIBS}}}.

 Tests driver dynHelloWorld, dynlibs T3807 and T5373 fail here with
 unresolved symbols from ffi when built with the in-tree libffi.

 I will reopen, assign to me, and prepare a patch.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5743#comment:16>
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