so you can specify the instance context yourself
    ? When deriving the instance for (Fractional CTimer)

/tmp/ghc57171_0/ghc_1.hscpp:642:111: error:
    ? No instance for (Floating Int32)
        arising from the 'deriving' clause of a data type declaration
      Possible fix:
        use a standalone 'deriving instance' declaration,
          so you can specify the instance context yourself
    ? When deriving the instance for (Floating CTimer)

/tmp/ghc57171_0/ghc_1.hscpp:642:120: error:
    ? No instance for (RealFrac Int32)
        arising from the 'deriving' clause of a data type declaration
      Possible fix:
        use a standalone 'deriving instance' declaration,
          so you can specify the instance context yourself
    ? When deriving the instance for (RealFrac CTimer)

/tmp/ghc57171_0/ghc_1.hscpp:642:129: error:
    ? No instance for (RealFloat Int32)
        arising from the 'deriving' clause of a data type declaration
      Possible fix:
        use a standalone 'deriving instance' declaration,
          so you can specify the instance context yourself
    ? When deriving the instance for (RealFloat CTimer)
libraries/base/ghc.mk:4: recipe for target 'libraries/base/dist-install/build/System/Posix/Types.o' failed
gmake[1]: *** [libraries/base/dist-install/build/System/Posix/Types.o] Error 1
Makefile:122: recipe for target 'all' failed
gmake: *** [all] Error 2