Resolving dependencies...
Downloading cairo-0.12.1...
[1 of 2] Compiling SetupWrapper     ( /tmp/cairo-0.12.1-24539/cairo-0.12.1/SetupWrapper.hs, /tmp/cairo-0.12.1-24539/cairo-0.12.1/dist/setup/SetupWrapper.o )
[2 of 2] Compiling Main             ( /tmp/cairo-0.12.1-24539/cairo-0.12.1/Setup.hs, /tmp/cairo-0.12.1-24539/cairo-0.12.1/dist/setup/Main.o )
Linking /tmp/cairo-0.12.1-24539/cairo-0.12.1/dist/setup/setup ...
[1 of 2] Compiling Gtk2HsSetup      ( Gtk2HsSetup.hs, dist/setup-wrapper/Gtk2HsSetup.o )
[2 of 2] Compiling Main             ( SetupMain.hs, dist/setup-wrapper/Main.o )
Linking dist/setup-wrapper/setup ...
Configuring cairo-0.12.1...
Building cairo-0.12.1...
Preprocessing library cairo-0.12.1...
[ 1 of 17] Compiling Graphics.Rendering.Cairo.Matrix ( dist/build/Graphics/Rendering/Cairo/Matrix.hs, dist/build/Graphics/Rendering/Cairo/Matrix.o )
[ 2 of 17] Compiling Graphics.Rendering.Cairo.Types ( dist/build/Graphics/Rendering/Cairo/Types.hs, dist/build/Graphics/Rendering/Cairo/Types.o )

Graphics/Rendering/Cairo/Types.chs:360:12:
    Could not deduce (Eq a) arising from a use of `toBool'
    from the context (Num a)
      bound by the type signature for cToBool :: Num a => a -> Bool
      at Graphics/Rendering/Cairo/Types.chs:359:12-29
    Possible fix:
      add (Eq a) to the context of
        the type signature for cToBool :: Num a => a -> Bool
    In the expression: toBool
    In an equation for `cToBool': cToBool = toBool
Failed to install cairo-0.12.1
cabal: Error: some packages failed to install:
cairo-0.12.1 failed during the building phase. The exception was:
ExitFailure 1