Resolving dependencies...
Downloading fst-0.9...
Warning: fst.cabal: Unknown fields: executable (line 32)
Fields allowed in this section:
main-is, buildable, build-tools, cpp-options, cc-options,
ld-options, pkgconfig-depends, frameworks, c-sources,
default-language, other-languages, default-extensions,
other-extensions, extensions, extra-libraries, extra-lib-dirs,
includes, install-includes, include-dirs, hs-source-dirs,
other-modules, ghc-prof-options, ghc-shared-options, ghc-options,
hugs-options, nhc98-options, jhc-options
Configuring fst-0.9...
Building fst-0.9...
Preprocessing library fst-0.9...

FST/Alex.hs:1:1:
    Ambiguous module name `Prelude':
      it was found in multiple packages: base haskell98-2.0.0.2
Failed to install fst-0.9
cabal: Error: some packages failed to install:
fst-0.9 failed during the building phase. The exception was:
ExitFailure 1