Add gcc and g++ to Debian and Ubuntu clang images

Author: bthomee

docker/debian/Dockerfile

@@ -95,6 +95,7 @@ update-alternatives --install \
 update-alternatives --auto cc
 update-alternatives --auto gcc
 EOF
+# Set the compiler environment variables to point to the GCC binaries.
 ENV CC=/usr/bin/gcc
 ENV CXX=/usr/bin/g++
 
@@ -154,6 +155,21 @@ FROM base AS clang
 # This is not inherited from base image, ensure no manual interaction needed.
 ARG DEBIAN_FRONTEND=noninteractive
 
+# Some build dependencies require GCC to be available.
+COPY --from=gcc-src /usr/local/ /usr/local/
+COPY --from=gcc-src /etc/ld.so.conf.d/*.conf /etc/ld.so.conf.d/
+RUN <<EOF
+ldconfig -v
+dpkg-divert --divert /usr/bin/gcc.orig --rename /usr/bin/gcc
+update-alternatives --install /usr/bin/gcc gcc /usr/local/bin/gcc 100
+update-alternatives --install \
+  /usr/bin/gcc gcc /usr/local/bin/gcc 100 \
+  --slave /usr/bin/g++ g++ /usr/local/bin/g++ \
+  --slave /usr/bin/gcc-ar gcc-ar /usr/local/bin/gcc-ar \
+  --slave /usr/bin/gcc-nm gcc-nm /usr/local/bin/gcc-nm \
+  --slave /usr/bin/gcc-ranlib gcc-ranlib /usr/local/bin/gcc-ranlib
+EOF
+
 # Install Clang. Use the LLVM apt repository to access the latest versions. We
 # must repeat the DEBIAN_VERSION argument here, as it is not inherited from the
 # base or source images.
@@ -178,7 +194,7 @@ update-alternatives --auto cc
 update-alternatives --auto clang
 update-alternatives --auto llvm-cov
 EOF
-
+# Set the compiler environment variables to point to the GCC binaries.
 ENV CC=/usr/bin/clang-${CLANG_VERSION}
 ENV CXX=/usr/bin/clang++-${CLANG_VERSION}
 

docker/debian/README.md

@@ -70,6 +70,7 @@ registry.
 DEBIAN_VERSION=bookworm
 CLANG_VERSION=17
 CONAN_VERSION=2.18.0
+GCC_VERSION=12
 GCOVR_VERSION=8.3
 CONTAINER_IMAGE=xrplf/ci/debian-${DEBIAN_VERSION}:clang-${CLANG_VERSION}
 
@@ -81,6 +82,7 @@ docker buildx build . \
   --build-arg CLANG_VERSION=${CLANG_VERSION} \
   --build-arg CONAN_VERSION=${CONAN_VERSION} \
   --build-arg DEBIAN_VERSION=${DEBIAN_VERSION} \
+  --build-arg GCC_VERSION=${GCC_VERSION} \
   --build-arg GCOVR_VERSION=${GCOVR_VERSION} \
   --tag ${CONTAINER_REGISTRY}/${CONTAINER_IMAGE}
 ```

docker/rhel/Dockerfile

@@ -64,6 +64,7 @@ update-alternatives \
 update-alternatives --auto cc
 update-alternatives --auto gcc
 EOF
+# Set the compiler environment variables to point to the GCC binaries.
 ENV CC=/usr/bin/gcc
 ENV CXX=/usr/bin/g++
 
@@ -126,7 +127,7 @@ rm -rf /var/cache/dnf/*
 update-alternatives --install /usr/bin/cc cc /usr/bin/clang 999
 update-alternatives --auto cc
 EOF
-
+# Set the compiler environment variables to point to the GCC binaries.
 ENV CC=/usr/bin/clang
 ENV CXX=/usr/bin/clang++
 

docker/ubuntu/Dockerfile

@@ -82,6 +82,7 @@ update-alternatives \
 update-alternatives --auto cc
 update-alternatives --auto gcc
 EOF
+# Set the compiler environment variables to point to the GCC binaries.
 ENV CC=/usr/bin/gcc
 ENV CXX=/usr/bin/g++
 
@@ -138,6 +139,21 @@ FROM base AS clang
 # This is not inherited from base image, ensure no manual interaction needed.
 ARG DEBIAN_FRONTEND=noninteractive
 
+# Some build dependencies require GCC to be available.
+ARG GCC_VERSION
+RUN <<EOF
+apt-get update
+apt-get install -y --no-install-recommends \
+    gcc-${GCC_VERSION} \
+    g++-${GCC_VERSION} \
+    debhelper
+apt-get clean
+rm -rf /var/lib/apt/lists/*
+update-alternatives \
+    --install /usr/bin/gcc gcc /usr/bin/gcc-${GCC_VERSION} 100 \
+    --slave /usr/bin/g++ g++ /usr/bin/g++-${GCC_VERSION}
+EOF
+
 # Install Clang.
 ARG CLANG_VERSION
 RUN <<EOF
@@ -157,7 +173,7 @@ update-alternatives --auto cc
 update-alternatives --auto clang
 update-alternatives --auto llvm-cov
 EOF
-
+# Set the compiler environment variables to point to the GCC binaries.
 ENV CC=/usr/bin/clang-${CLANG_VERSION}
 ENV CXX=/usr/bin/clang++-${CLANG_VERSION}
 

docker/ubuntu/README.md

@@ -66,6 +66,7 @@ registry.
 UBUNTU_VERSION=noble
 CLANG_VERSION=18
 CONAN_VERSION=2.18.0
+GCC_VERSION=14
 GCOVR_VERSION=8.3
 CONTAINER_IMAGE=xrplf/ci/ubuntu-${UBUNTU_VERSION}:clang-${CLANG_VERSION}
 
@@ -76,6 +77,7 @@ docker buildx build . \
   --build-arg BUILDKIT_INLINE_CACHE=1 \
   --build-arg CLANG_VERSION=${CLANG_VERSION} \
   --build-arg CONAN_VERSION=${CONAN_VERSION} \
+  --build-arg GCC_VERSION=${GCC_VERSION} \
   --build-arg GCOVR_VERSION=${GCOVR_VERSION} \
   --build-arg UBUNTU_VERSION=${UBUNTU_VERSION} \
   --tag ${CONTAINER_REGISTRY}/${CONTAINER_IMAGE}