[Docker] Fix the docker build by bumping CMake version in Dockerfile (t…

…aichi-dev#2348)

* Build CMake from source than relying on the default version shipped with Ubuntu LTS.

* Add a missing ENV VAR TI_IN_DOCKER.

Dockerfile

@@ -11,7 +11,6 @@ RUN apt-get update && \
                        python3-pip \
                        libtinfo-dev \
                        clang-8 \
-                       cmake \
                        wget \
                        git \
                        libx11-dev \
@@ -22,14 +21,27 @@ RUN apt-get update && \
                        libglu1-mesa-dev \
                        freeglut3-dev \
                        mesa-common-dev \
-                       libtinfo5
+                       libtinfo5 \
+                       build-essential \
+                       libssl-dev
 
 # Install Taichi's Python dependencies
 RUN python3 -m pip install --user setuptools astor pybind11 pylint sourceinspect
 RUN python3 -m pip install --user pytest pytest-rerunfailures pytest-xdist yapf
 RUN python3 -m pip install --user numpy GitPython coverage colorama autograd
 
+# Install the latest version of CMAKE v3.20.2 from source
+RUN apt purge --auto-remove cmake
+RUN wget https://github.com/Kitware/CMake/releases/download/v3.20.2/cmake-3.20.2.tar.gz
+RUN tar -zxvf cmake-3.20.2.tar.gz
+RUN cd cmake-3.20.2
+WORKDIR /cmake-3.20.2
+RUN ./bootstrap
+RUN make -j 8
+RUN make install
+
 # Intall LLVM 10
+WORKDIR /
 ENV CC=/usr/bin/clang-8
 ENV CXX=/usr/bin/clang++-8
 RUN wget https://github.com/llvm/llvm-project/releases/download/llvmorg-10.0.0/llvm-10.0.0.src.tar.xz
@@ -56,5 +68,7 @@ ENV TAICHI_REPO_DIR="/taichi-dev/taichi/"
 ENV PYTHONPATH="$TAICHI_REPO_DIR/python:$PYTHONPATH"
 ENV LANG="C.UTF-8"
 
+# Add Docker specific ENV
+ENV TI_IN_DOCKER=true
 WORKDIR /taichi-dev/taichi
 CMD /bin/bash