chore(release) install Python 3.8+ in older distributions

Fixing V8 build issues, see NVIDIA/DeepLearningExamples#1016

Fixes #430

assets/release/Dockerfiles/Dockerfile.amd64.centos7

@@ -20,6 +20,13 @@ RUN yum install -y epel-release && \
         perl-IPC-Cmd \
         perl-Test-Simple
 
+# Install Python 3.8+ (required by V8's GN build system)
+RUN yum -y install centos-release-scl-rh centos-release-scl && \
+    yum --enablerepo=centos-sclo-rh -y install rh-python38 && \
+    echo 'source /opt/rh/rh-python38/enable; export X_SCLS="`scl enable rh-python38 'echo $X_SCLS'`"' >> /etc/profile.d/python38.sh && \
+    echo 'source /opt/rh/rh-python38/enable; export X_SCLS="`scl enable rh-python38 'echo $X_SCLS'`"' >> ~/.bashrc && \
+    echo "scl enable rh-python38" >> ~/.bashrc
+
 ENV RUSTUP_HOME=/usr/local/rustup CARGO_HOME=/usr/local/cargo
 ENV PATH $CARGO_HOME/bin:$PATH
 RUN ln -nfs $(which cmake3) /usr/bin/cmake
@@ -31,3 +38,5 @@ RUN mkdir -p "$CARGO_HOME" && mkdir -p "$RUSTUP_HOME" && \
 # https://github.com/WebAssembly/wasm-c-api/blob/master/include/wasm.h#L29
 # and ensure a more recent libstdc++ is found
 ENV LD_FLAGS="-Wl,--allow-multiple-definition -L/opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8"
+
+SHELL ["/bin/bash", "-l", "-c"]

assets/release/Dockerfiles/Dockerfile.amd64.centos8

@@ -13,7 +13,7 @@ RUN sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-Linux-* && \
         libstdc++-devel \
         libatomic \
         perl \
-        python3 \
+        python39 \
         git \
         glib2-devel
 

assets/release/Dockerfiles/Dockerfile.amd64.ubuntu-18.04

@@ -26,8 +26,17 @@ RUN apt-get install -y --no-install-recommends \
         pip3 install scikit-build && \
         pip3 install cmake
 
+# Install Python 3.8+ (required by V8's GN build system)
+RUN apt-get install -y software-properties-common && \
+    add-apt-repository -y ppa:deadsnakes/ppa && \
+    apt-get update && \
+    apt-get install -y python3.8 && \
+    echo 'alias python3="python3.8"' >> ~/.bashrc
+
 ENV RUSTUP_HOME=/usr/local/rustup CARGO_HOME=/usr/local/cargo
 ENV PATH $CARGO_HOME/bin:$PATH
 RUN mkdir -p "$CARGO_HOME" && mkdir -p "$RUSTUP_HOME" && \
     curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain stable && \
     chmod -R a=rwX $CARGO_HOME $RUSTUP_HOME
+
+SHELL ["/bin/bash", "-l", "-c"]

util/release.sh

@@ -373,6 +373,19 @@ release_bin() {
 
     notice "Building $arch binary..."
 
+    notice "Debug"
+    ps -p $$
+    if [ -x "$(command -v python)" ]; then
+        python -V
+    else
+        echo "no python"
+    fi
+    if [ -x "$(command -v python3)" ]; then
+        python3 -V
+    else
+        echo "no python3"
+    fi
+
     if [ "$(get_distro)" = "centos7" ]; then
         notice "Enabling devtoolset-8 for CentOS..."
         source /opt/rh/devtoolset-8/enable