エラー内容

brew install cabal-install                                                                                                                                
==> Downloading http://www.haskell.org/cabal/release/cabal-install-0.14.0/cabal-install-0.14.0.tar.gz
Already downloaded: /Library/Caches/Homebrew/cabal-install-0.14.0.tar.gz
==> sh bootstrap.sh
Could not find task "__numeric_version".
Could not find task "__numeric_version".
bootstrap.sh: line 81: [: too many arguments

Error during cabal-install bootstrap:
Version mismatch between ghc and ghc-pkg If you set the GHC variable then set GHC_PKG too
==> Build Environment
CPU: dual-core 64-bit penryn
MacOS: 10.7.4-i386
Xcode: 4.3.2
CC: /usr/bin/clang
CXX: /usr/bin/clang++ => /usr/bin/clang
LD: /usr/bin/clang
CFLAGS: -Os -w -pipe -march=native -Qunused-arguments
CXXFLAGS: -Os -w -pipe -march=native -Qunused-arguments
MAKEFLAGS: -j2
Error: Failed executing: sh bootstrap.sh (cabal-install.rb:12)
These existing issues may help you:
    https://github.com/mxcl/homebrew/issues/12155
Otherwise, please report the bug:
    https://github.com/mxcl/homebrew/wiki/reporting-bugs

解決

Version mismatch between ghc and ghc-pkg If you set the GHC variable then set GHC_PKG too が直接の原因っぽい。

GHC=/usr/local/bin/ghc brew install cabal-install

としたら入った

原因

わかった。
which ghc が ~/.gem/ruby/1.9.1/bin/ghc だった

http://rubygems.org/gems/github_cli
"Glasgow Haskell Compiler" ではない(ズコー)