Add a 32-bit task to Cirrus CI config

.cirrus.yml

@@ -77,6 +77,13 @@ debian9_task:
     << : *RESOURCES_TEMPLATE
   << : *CI_TEMPLATE
 
+debian9_32bit_task:
+  container:
+    # Debian 9 EOL: June 2022
+    dockerfile: ci/debian-9-32bit/Dockerfile
+    << : *RESOURCES_TEMPLATE
+  << : *CI_TEMPLATE
+
 ubuntu18_task:
   container:
     # Ubuntu 18.04 EOL: April 2023

ci/debian-9-32bit/Dockerfile

@@ -0,0 +1,40 @@
+FROM i386/debian:9
+
+RUN apt-get update && apt-get -y install \
+    git \
+    cmake \
+    make \
+    gcc \
+    g++ \
+    flex \
+    bison \
+    libpcap-dev \
+    libssl-dev \
+    python3 \
+    python3-dev \
+    python3-pip\
+    swig \
+    zlib1g-dev \
+    libkrb5-dev \
+    bsdmainutils \
+    sqlite3 \
+    curl \
+    wget \
+    xz-utils \
+    clang-7 \
+    libc++-7-dev \
+    libc++abi-7-dev \
+  && rm -rf /var/lib/apt/lists/*
+
+RUN update-alternatives --install /usr/bin/cc cc /usr/bin/clang-7 100
+RUN update-alternatives --install /usr/bin/c++ c++ /usr/bin/clang++-7 100
+
+# Many distros adhere to PEP 394's recommendation for `python` = `python2` so
+# this is a simple workaround until we drop Python 2 support and explicitly
+# use `python3` for all invocations (e.g. in shebangs).
+RUN ln -sf /usr/bin/python3 /usr/local/bin/python
+RUN ln -sf /usr/bin/pip3 /usr/local/bin/pip
+
+RUN pip install junit2html
+
+ENV CXXFLAGS=-stdlib=libc++