Initial attempt with CI

clang-format-16.dockerfile

@@ -0,0 +1,34 @@
+# Stage 1: Build environment
+FROM docker.io/redhat/ubi8 AS builder
+
+LABEL org.opencontainers.image.source https://github.com/cwpearson/clang-format
+
+RUN dnf install -y \
+    cmake \
+    gcc \
+    gcc-c++ \
+    python3 \
+    wget \
+    xz \
+    && dnf clean all
+
+RUN wget -q https://github.com/llvm/llvm-project/releases/download/llvmorg-16.0.6/llvm-project-16.0.6.src.tar.xz \
+    && tar -xf llvm-project-16.0.6.src.tar.xz
+RUN cmake -S llvm-project-16.0.6.src/llvm -B build \
+  -DLLVM_ENABLE_PROJECTS='clang' \
+  -DCMAKE_BUILD_TYPE=MinSizeRel \
+  -DLLVM_TARGETS_TO_BUILD=""
+RUN make -C build -j$(nproc) install
+
+# base final image off ubi8-micro
+FROM docker.io/redhat/ubi8-micro
+
+# clang-format-16 links this
+COPY --from=builder /lib64/libstdc++.so.6 /lib64/libstdc++.so.6
+# keep clang-format binary only
+COPY --from=builder /usr/local/bin/clang-format /usr/local/bin/clang-format
+# also provide clang-format-16
+RUN ln -s /usr/local/bin/clang-format /usr/local/bin/clang-format-16
+
+# expect caller to map $PWD into /src with -v flag
+WORKDIR /src