message: Use remote part's implementation of ccache
  This patch uses the remote part implementation of ccache to shrink
  the lines of code in the recipe.  The implementation of the remote
  part can be acquired by running `snapcraft define ccache`.
diff: @@ -326,40 +326,6 @@ parts:
  ccache:
  after:
  - gcc-6
  - override-pull: 'true'
  - build-packages:
  - - ccache
  - plugin: nil
  - override-build: |
  - mkdir \
  - --parents \
  - "${SNAPCRAFT_PART_INSTALL}"/bin
  - ln \
  - --force \
  - --symbolic \
  - "$(which ccache)" \
  - "${SNAPCRAFT_PART_INSTALL}"/bin/gcc-6
  - ln \
  - --force \
  - --symbolic \
  - "$(which ccache)" \
  - "${SNAPCRAFT_PART_INSTALL}"/bin/g++-6
  - ln \
  - --force \
  - --symbolic \
  - ./gcc-6 \
  - "${SNAPCRAFT_PART_INSTALL}"/bin/gcc
  - ln \
  - --force \
  - --symbolic \
  - ./g++-6 \
  - "${SNAPCRAFT_PART_INSTALL}"/bin/g++
  - filesets:
  - executables:
  - - bin/*
  - stage:
  - - $executables
  - override-prime: 'true'
  # This pseudo part setups version 6 of GCC, which is not available
  # in Ubuntu 16.04 software source.
  