[GHC] #7921: DSO linking bug in unix package

[GHC]

#7921: DSO linking bug in unix package
-------------------------------+--------------------------------------------
Reporter:  SimonHengel         |          Owner:                
    Type:  bug                 |         Status:  new           
Priority:  normal              |      Component:  libraries/unix
 Version:  7.6.3               |       Keywords:                
      Os:  Linux               |   Architecture:  x86_64 (amd64)
 Failure:  Compile-time crash  |      Blockedby:                
Blocking:                      |        Related:                
-------------------------------+--------------------------------------------
 {{{unix}}} depends on {{{libpthread}}}, but it's not listed under
 {{{extra-libraries}}} in the cabal file.  For that reason some programs
 fail to build on Ubuntu 13.04.

 Steps to reproduce:
 {{{
 -- Main.hs
 import System.Posix.Semaphore

 main :: IO ()
 main = do
   semUnlink "foo"
 }}}
 {{{
 $ ghc --make Main.hs
 }}}

 Expected result: Program is compiled and linked.

 Actual result: Liking fails with
 {{{
 /usr/bin/ld:
 /home/foo/.install/haskell/ghc-7.6.2/lib/ghc-7.6.2/unix-2.6.0.1/libHSunix-2.6.0.1.a(Semaphore__5.o):
 undefined reference to symbol 'sem_unlink@@GLIBC_2.2.5'
 /usr/bin/ld: note: 'sem_unlink@@GLIBC_2.2.5' is defined in DSO /lib/x86_64
 -linux-gnu/libpthread.so.0 so try adding it to the linker command line
 /lib/x86_64-linux-gnu/libpthread.so.0: could not read symbols: Invalid
 operation
 collect2: error: ld returned 1 exit status
 }}}

 This is related to
 https://fedoraproject.org/wiki/UnderstandingDSOLinkChange.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7921>
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