Resolving dependencies...
Downloading AVar-0.0.1...
Configuring AVar-0.0.1...
Building AVar-0.0.1...
Preprocessing library AVar-0.0.1...

Data/AVar.hs:27:8:
    Could not find module `System'
    It is a member of the hidden package `haskell98-2.0.0.2'.
    Perhaps you need to add `haskell98' to the build-depends in your .cabal file.
    Use -v to see a list of the files searched for.
Failed to install AVar-0.0.1
cabal: Error: some packages failed to install:
AVar-0.0.1 failed during the building phase. The exception was:
ExitFailure 1