Hi, I'm having trouble building my Haskell library with GHC 7.8.2 and Cabal 1.20.0.2 on OSX 10.9.3 with both -staticlib and -threaded enabled. The library I'm building exports several functions using FFI to be called from ObjectiveC in an Xcode project. This works fine with just -staticlib enabled, but now I realize I need to call into my Haskell library from multiple OS-threads simultaneously. But when I add -threaded to ghc-options I get an error when linking: error: libtool: can't locate file for: -lpthread error: libtool: file: -lpthread is not an object file (not allowed in a library) The linker command that fails looks like this (... replaces a bunch of -l and -L options): libtool -static -o liba.a dist/build/HsCocoa.o ... -lCffi -lpthread In /usr/lib I have a libpthread.dylib that links to libSystem.dylib, but no libpthread.a. I was under the impression that libpthread was included with the system install. Is this supposed to work or am I misunderstanding something basic? :) Any help would be greatly appreciated! The project source is available on github: https://github.com/froden/digipostarkiv (I asked the same question on stackoverflow: http://stackoverflow.com/q/24096257/777411) Best regards, Frode Nerbråten