I did this:

sudo nix-env -i libiconv
sudo nix-env -i ghc-7.4.2

But the build fails with:

checking for library containing iconv... no
configure: error: iconv is required on non-Windows platforms
make[1]: *** [libraries/base/dist-install/package-data.mk] Error 1
make: *** [all] Error 2
builder for `/nix/store/kkp7j96ic54pcm6ymkxrgpvcjfsy3l9v-ghc-7.4.2.drv' failed with exit code 2
error: build of `/nix/store/kkp7j96ic54pcm6ymkxrgpvcjfsy3l9v-ghc-7.4.2.drv' failed

libiconv should be a dependency of ghc-7.4.2, and the GHC build should use –with-iconv-includes and –with-iconv-libraries.

Submitted by John Wiegley on 14 August 2012 at 19:05