Hi All, I am still having difficulty getting a plain GHC build with INTEGER_LIBRARY = integer-simple. (I outlined my problem here yesterday <http://www.haskell.org/pipermail/glasgow-haskell-users/2011-July/020631.htm l> .) I suspected my failure to get a vanilla build (with GMP) was a minor issue with RHEL 5 and indeed a vanilla build of the the compiler goes through no problem on RHEL 6, producing a working 6.12.3 GHC installation. But when I repeat with INTEGER_LIBRARY = integer-simple (on quick test) I get (the now familiar): GHCi, version 6.12.3: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. ghc: /usr/local/ghc/6.12.3-si/lib/ghc-6.12.3/integer-simple-0.1.0.0/HSinteger-sim ple-0.1.0.0.o: unknown symbol `base_ControlziExceptionziBase_patError_info' Loading package integer-simple ... linking ... ghc: unable to load package `integer-simple' RHEL 5 and 6 are very different development environments yet all my attempts to build with a variety of source trees from 6.12.1 to 7.0.4 with INTEGER_LIBRARY = integer-simple has ended here. There is clearly something I am doing wrong! (Though it is difficult to see what.) Does anybody have any idea what could be causing this? Is anybody else doing integer-simple builds? It would be nice to get some info on the configurations that are working. Thanks in advance! Chris