diff --git a/docker/Dockerfile-alpine-320 b/docker/Dockerfile-alpine-320
index 4870140..90494fe 100644
--- a/docker/Dockerfile-alpine-320
+++ b/docker/Dockerfile-alpine-320
@@ -34,7 +34,7 @@ RUN apk add -q --no-cache R-dev curl ca-certificates bash g++ tzdata openjdk17 t
 # LDFLAGS+=-fPIC -> arrow (https://github.com/r-hub/r-minimal/blob/main/examples/arrow/Dockerfile)
 # dbarts: CFLAGS += -flax-vector-conversions (https://github.com/vdorie/dbarts/issues/66)
 # CXXFLAGS: -> Rcpp 
-RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCXXFLAGS=-D__MUSL__\nCPPFLAGS=-D__MUSL__\nCFLAGS += -flax-vector-conversions\nLDFLAGS+=-fPIC\nCC=ccache gcc\nCPP=ccache gcc\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" > /root/.R/Makevars'
+RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCXXFLAGS=-D__MUSL__\nCPPFLAGS=-D__MUSL__\nCFLAGS += -flax-vector-conversions\nLDFLAGS+=-fPIC\nCC=ccache gcc\nCPP=gcc -E\nCXXCPP=gcc -e\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" > /root/.R/Makevars'
 
 # R repos
 RUN bash -c 'echo -e "options(crayon.enabled = TRUE, Ncpus = ${NCPUS}, future.globals.onReference = NULL, repos = structure(c(CRAN = \"https://cloud.r-project.org\", INLA = \"https://inla.r-inla-download.org/R/stable\")))" > /root/.Rprofile'
diff --git a/docker/Dockerfile-redhat-8 b/docker/Dockerfile-redhat-8
index af600b5..3c32bd5 100644
--- a/docker/Dockerfile-redhat-8
+++ b/docker/Dockerfile-redhat-8
@@ -32,7 +32,7 @@ RUN R -q -e 'install.packages("pak", repos = sprintf("https://r-lib.github.io/p/
 
 ### Makevars
 # dbarts: CFLAGS += -flax-vector-conversions (https://github.com/vdorie/dbarts/issues/66)
-RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCFLAGS += -flax-vector-conversions\nCC=ccache gcc\nCPP=ccache gcc\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" >> /root/.R/Makevars'
+RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCFLAGS += -flax-vector-conversions\nCC=ccache gcc\nCPP=gcc -E\nCXXCPP=gcc -e\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" >> /root/.R/Makevars'
 
 # R repos
 RUN bash -c 'echo -e "options(crayon.enabled = TRUE, Ncpus = ${NCPUS}, future.globals.onReference = NULL, repos = structure(c(CRAN = \"https://cloud.r-project.org\", INLA = \"https://inla.r-inla-download.org/R/stable\")))" > /root/.Rprofile'
diff --git a/docker/Dockerfile-redhat-9 b/docker/Dockerfile-redhat-9
index 43abb98..ce7f328 100644
--- a/docker/Dockerfile-redhat-9
+++ b/docker/Dockerfile-redhat-9
@@ -32,7 +32,7 @@ RUN R -q -e 'install.packages("pak", repos = sprintf("https://r-lib.github.io/p/
 
 ### Makevars
 # dbarts: CFLAGS += -flax-vector-conversions (https://github.com/vdorie/dbarts/issues/66)
-RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCFLAGS += -flax-vector-conversions\nCC=ccache gcc\nCPP=ccache gcc\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" >> /root/.R/Makevars'
+RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCFLAGS += -flax-vector-conversions\nCC=ccache gcc\nCPP=gcc -E\nCXXCPP=gcc -e\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" >> /root/.R/Makevars'
 
 # R repos
 RUN bash -c 'echo -e "options(crayon.enabled = TRUE, Ncpus = ${NCPUS}, future.globals.onReference = NULL, repos = structure(c(CRAN = \"https://cloud.r-project.org\", INLA = \"https://inla.r-inla-download.org/R/stable\")))" > /root/.Rprofile'
diff --git a/docker/Dockerfile-ubuntu-2204 b/docker/Dockerfile-ubuntu-2204
index 9d19986..70b75ac 100644
--- a/docker/Dockerfile-ubuntu-2204
+++ b/docker/Dockerfile-ubuntu-2204
@@ -30,7 +30,7 @@ RUN R -q -e 'install.packages("pak", repos = sprintf("https://r-lib.github.io/p/
 
 ### Makevars
 # dbarts: CFLAGS += -flax-vector-conversions (https://github.com/vdorie/dbarts/issues/66)
-RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCFLAGS += -flax-vector-conversions\nCC=ccache gcc\nCPP=ccache gcc\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" >> /root/.R/Makevars'
+RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCFLAGS += -flax-vector-conversions\nCC=ccache gcc\nCPP=gcc -E\nCXXCPP=gcc -e\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" >> /root/.R/Makevars'
 
 # R repos
 RUN bash -c 'echo -e "options(pkg.sysreqs_verbose = TRUE, crayon.enabled = TRUE, Ncpus = ${NCPUS}, future.globals.onReference = NULL, repos = structure(c(CRAN = \"https://cloud.r-project.org\", INLA = \"https://inla.r-inla-download.org/R/stable\")))" > ~/.Rprofile'
diff --git a/docker/Dockerfile-ubuntu-2404 b/docker/Dockerfile-ubuntu-2404
index d7e844b..ee62f7b 100644
--- a/docker/Dockerfile-ubuntu-2404
+++ b/docker/Dockerfile-ubuntu-2404
@@ -30,7 +30,7 @@ RUN R -q -e 'install.packages("pak", repos = sprintf("https://r-lib.github.io/p/
 
 ### Makevars
 # dbarts: CFLAGS += -flax-vector-conversions (https://github.com/vdorie/dbarts/issues/66)
-RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCFLAGS += -flax-vector-conversions\nCC=ccache gcc\nCPP=ccache gcc\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" >> /root/.R/Makevars'
+RUN mkdir -p /root/.R && bash -c 'echo -e "CXX_STD = CXX14\nCFLAGS += -flax-vector-conversions\nCC=ccache gcc\nCPP=gcc -E\nCXXCPP=gcc -e\nCXX=ccache g++\nCXX11=ccache g++\nCXX14=ccache g++\nCXX17=ccache g++\nF77=ccache /usr/bin/gfortran\nFC=ccache /usr/bin/gfortran" >> /root/.R/Makevars'
 
 # R repos
 RUN bash -c 'echo -e "options(pkg.sysreqs_verbose = TRUE, crayon.enabled = TRUE, Ncpus = ${NCPUS}, future.globals.onReference = NULL, repos = structure(c(CRAN = \"https://cloud.r-project.org\", INLA = \"https://inla.r-inla-download.org/R/stable\")))" > ~/.Rprofile'