The issue was:
Compatibility with CMake < 3.5 has been removed from CMake.
# Upstream expat doesn't ship devel? let's build it then...
# ADD https://github.com/libexpat/libexpat/releases/download/R_2_4_1/expat-win32bin-2.4.1.exe C:\TEMP\expat.exe
# RUN C:\TEMP\expat.exe /VERYSILENT /SUPPRESSMSGBOXES /NORESTART /SP-
-RUN git clone --depth 1 --branch R_2_4_2 https://github.com/libexpat/libexpat
+RUN git clone --depth 1 --branch R_2_8_2 https://github.com/libexpat/libexpat
WORKDIR "/libexpat/expat"
RUN cmake --install-prefix c:/ -G '"Visual Studio 15 2017"' -A x64 .
RUN cmake --build . --config Release