anchor.diff:  
   # Install macosx build tools (osxcross) and libraries (macports).
   ENV PATH /opt/osxcross/target/bin:${PATH}
  -
   RUN export SDK_VERSION=10.13 &&                               \
       export MACOSX_DEPLOYMENT_TARGET=${SDK_VERSION} &&         \
       export UNATTENDED=1 &&                                    \
  
positive.code:     wget -P tarballs https://github.com/phracker/MacOSX-SDKs/releases/download/${SDK_VERSION}/MacOSX${SDK_VERSION}.sdk.tar.xz && \
      ./build.sh &&                                             \
      osxcross-macports install                                 \
  	lua50                                                 \
  	lua51                                                 \
  	lua52                                                 \
  	openjdk8                                              \
  	python27                                              \
  	python35                                              \
  
negative.code: 	ruby25                                                \
  	ruby26
  
  # Install windows build tools (mingw) and libraries.
  RUN mkdir -p /opt/wincross/archives                && \
      cd /opt/wincross                               && \
      mkdir java                                     && \
      wget -O archives/jdk8.zip https://github.com/AdoptOpenJDK/openjdk8-binaries/releases/download/jdk8u252-b09.1/OpenJDK8U-jdk_x86-32_windows_hotspot_8u252b09.zip && \
      unzip -d archives/java archives/jdk8.zip       && \
      mv archives/java/jdk*/* java                   && \
      mkdir lua51                                    && \
      wget -O archives/lua51.zip https://sourceforge.net/projects/luabinaries/files/5.1.5/Windows%20Libraries/Dynamic/lua-5.1.5_Win64_dllw6_lib.zip && \
      unzip -d lua51 archives/lua51.zip              && \
      mkdir lua52                                    && \
      wget -O archives/lua52.zip https://sourceforge.net/projects/luabinaries/files/5.2.4/Windows%20Libraries/Dynamic/lua-5.2.4_Win64_dllw6_lib.zip && \
      unzip -d lua52 archives/lua52.zip              && \
      mkdir lua53                                    && \
      wget -O archives/lua53.zip https://sourceforge.net/projects/luabinaries/files/5.3.5/Windows%20Libraries/Dynamic/lua-5.3.5_Win64_dllw6_lib.zip && \
      unzip -d lua53 archives/lua53.zip              && \
      rm -rf archives
  
  # Run environment.
  CMD /bin/bash
  