Specify compiler in DUNE testing image

* Split setup CI stage into two jobs for GCC and Clang
* Add compiler (CC) as ARG in Dockerfile
* Remove dune-env-clang.dockerfile

.gitlab-ci.yml

@@ -45,8 +45,12 @@ setup:dune-env: &setup
       --build-arg PROCNUM=$CPUS_DIND
       -t $DUNE_ENV_IMAGE .
     - docker push $DUNE_ENV_IMAGE
-    - docker build -f docker/dune-env-clang.dockerfile
-      --build-arg DUNE_ENV_IMAGE=$DUNE_ENV_IMAGE
+
+setup:dune-env-clang:
+  <<: *setup
+  script:
+    - docker build -f docker/dune-env.dockerfile
+      --build-arg CC=clang
       --build-arg PROCNUM=$CPUS_DIND
       -t ${DUNE_ENV_IMAGE}-clang .
     - docker push ${DUNE_ENV_IMAGE}-clang

docker/dune-env-clang.dockerfile

-ARG DUNE_ENV_IMAGE=dorie/dune-env
-FROM $DUNE_ENV_IMAGE
-RUN apt-get clean && apt-get update && apt-get install -y \
-    clang
-
-WORKDIR /opt/dune
-# clean directories and rebuild DUNE
-RUN ./dune-common/bin/dunecontrol exec "rm -rf build-cmake"
-RUN MAKE_FLAGS="-j ${PROCNUM}" \
-    CMAKE_FLAGS="-DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DDUNE_PYTHON_VIRTUALENV_SETUP=True -DDUNE_PYTHON_ALLOW_GET_PIP=True" \
-    ./dune-common/bin/dunecontrol all
\ No newline at end of file

docker/dune-env.dockerfile

@@ -2,12 +2,13 @@ FROM ubuntu:bionic
 LABEL maintainer="lriedel@iup.uni-heidelberg.de"
 # number of cores for parallel builds
 ARG PROCNUM=1
+# C++ compiler to be installed
+ARG CC=g++
 
 RUN apt-get clean && apt-get update && apt-get install -y \
+    ${CC} \
     cmake \
     doxygen \
-    gcc \
-    g++ \
     gfortran \
     git \
     libatlas-base-dev \