diff --git a/Dockerfile b/Dockerfile
index 44f664e3..47a32495 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,9 +5,9 @@ ARG APPNAME=app4triqs
 COPY requirements.txt /src/$APPNAME/requirements.txt
 RUN pip install -r /src/$APPNAME/requirements.txt
 
-COPY . $SRC/$APPNAME
+COPY --chown=build . $SRC/$APPNAME
 WORKDIR $BUILD/$APPNAME
-RUN chown -R build $SRC/$APPNAME .
+RUN chown build .
 USER build
 ARG BUILD_DOC=0
 RUN cmake $SRC/$APPNAME -DTRIQS_ROOT=${INSTALL} -DBuild_Documentation=${BUILD_DOC} && make -j2 && make test CTEST_OUTPUT_ON_FAILURE=1
diff --git a/Jenkinsfile b/Jenkinsfile
index 482320b9..ac8d06a4 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -48,7 +48,7 @@ for (int i = 0; i < dockerPlatforms.size(); i++) {
 
 /****************** osx builds (on host) */
 def osxPlatforms = [
-  ["gcc", ['CC=gcc-7', 'CXX=g++-7', 'FC=gfortran-7']],
+  ["gcc", ['CC=gcc-9', 'CXX=g++-9', 'FC=gfortran-9']],
   ["clang", ['CC=$BREW/opt/llvm/bin/clang', 'CXX=$BREW/opt/llvm/bin/clang++', 'CXXFLAGS=-I$BREW/opt/llvm/include', 'LDFLAGS=-L$BREW/opt/llvm/lib']]
 ]
 for (int i = 0; i < osxPlatforms.size(); i++) {