Pin a package?

Is there a way to tell cabal to refuse to upgrade a package? I'd like to pin my `bytestring` to the version that shipped with my GHC. I just had a weird experience. When I try to `cabal install iconv` (with my settings) it tried to downgrade my `bytestring`, when I download and do the configure+build by hand, it works, but when I try to install the local version it again begins to try to downgrade my bytestring. If I just `register --inplace` it works fine. Wut? -- Stephen Paul Weber, @singpolyma See http://singpolyma.net for how I prefer to be contacted edition right joseph