Problem installing unix-2.3.2.0

[Antoine Latter]

Hi Libraries,

cabal-install  tries to pull in unix-2.3.2.0 in it's install plan when
installing cabal-install, but it doesn't successfully install for me
under Ubuntu 9.10.

Here's some cut'n'paste of what I've tried:

$ cabal unpack unix-2.3.2.0
Downloading unix-2.3.2.0...
Unpacking to unix-2.3.2.0/

$ cd unix-2.3.2.0/

$ cabal install
<snip>
Building unix-2.3.2.0...

dist/build/System/Posix/Signals.hs:127:0:
     error: Signals.h: No such file or directory
cabal: Error: some packages failed to install:
unix-2.3.2.0 failed during the building phase. The exception was:
ExitFailure 1

$ find . | grep Signals
./System/Posix/Signals.hsc
./System/Posix/Signals
./System/Posix/Signals/Exts.hsc

unix-2.3.0.1 seems to have the same problem, and cabal-install can't
form a valid install plan for unix-2.3.0.0. I have hsc2hs in my path
at version 0.67, and I'm using GHC 6.12.1. Is there some step I'm
missing?

Thanks,
Antoine