macports で入れた cabal がアップグレードできなかった。 $ sudo port upgrade hs-cabal > Configuring hs-cabal Error: Target org.macports.configure returned: shell command "cd /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_devel_hs-cabal/work/cabal-install-0.6.2 && runhaskell Setup configure --ghc --prefix=/opt/local" returned error 1 Command output: Configuring cabal-inst