message: Dockerfile: checkout libtorrent when building the image, no need to do this for each build
diff: @@ -17,6 +17,7 @@ RUN apt install -y swig
  RUN apt install -y openjdk-11-jdk-headless
  RUN apt install -y gradle
  +ENV LIBTORRENT_REVISION="6aad9a463236f0e12f4c4808e4aa84aa0d8b7450"
  ENV BOOST_MAJOR="1"
  ENV BOOST_VERSION="73"
  ENV BOOST_MINOR="0"
  @@ -104,6 +105,17 @@ RUN cd /src/openssl-src \
  && make clean \
  && cd ..
  +# Prepare latest version of libtorrent
  +RUN rm -fr /src/libtorrent
  +RUN cd /src \
  + && git clone https://github.com/arvidn/libtorrent \
  + && cd libtorrent \
  + && git fetch origin RC_1_2 \
  + && git reset --hard ${LIBTORRENT_REVISION} \
  + && git submodule init \
  + && git submodule update \
  + && cd /
  +
  # Android cleanup (maybe not needed for jlibtorrent)
  RUN sed -i 's/POSIX_FADV_RANDOM 1/POSIX_FADV_RANDOM_NOOP 0/g' /src/android-toolchain-arm/sysroot/usr/include/linux/fadvise.h
  RUN sed -i 's/24/19/g' /src/android-toolchain-arm/sysroot/usr/include/stdio.h
  