Excerpts from Евгений Пермяков's message of Thu Nov 12 00:33:07 -0700 2009:

When I try cabal-install lambdabot (gentoo linux/amd64, ghc installed with portage), it runs fine until compiler tries to link readline package (some template haskell?). The problem caused by dirty trick, used in gentoo: the /usr/lib64/libreadline is a fake with script, redirecting ld to /lib64 . GHC is not redirected but simply fails with message "can't load .so/.DLL for: readline (/usr/lib64/libreadline.so: invalid ELF header)".

Yes, this is painful. There are discussions going on on ghc and on gentoo trackers for better ways to handle this. [1] [2] The problem is not gentoo specific though. Many other distros also use ld scripts, for example the same problem occurs using ubuntu.

So, the question is: is there any workaround? Copying library look like an option, but it is very, very dirty one. Is there a way to say ghc, which libreadline.so it should load?

To build lambdabot, and in other similar situations I have renamed the ld script temporarily and symlinked to the appropriate real .so then after the build put things back as they were. There are cases when this isn't sufficient, for example when the problem lib is needed for ongoing development project. Others more knowledgable can speak to how they've handled that. [1] http://hackage.haskell.org/trac/ghc/ticket/2615 [2] http://bugs.gentoo.org/290974 -- wmw