message: Install happy in Travis CI image
  Current versions of stack appear to need happy installed ahead of time
  to use the happy package.
diff: @@ -10,6 +10,10 @@ RUN apt-get update && \
  apt-get -y install \
  software-properties-common
  +# Components for gbc
  +RUN apt-get -y install \
  + happy
  +
  # Components for Boost
  RUN apt-get -y install \
  build-essential \
  