add --reuse flag to spack install calls

platforms/common/spack_utils.sh

@@ -16,7 +16,7 @@ function _install_spack() {
     echo "Found Compiler $(spack compiler info ${SPACK_COMPILER})"
   else
     echo "could not find compiler, will now try to install it... this may take a while"
-    spack install ${SPACK_COMPILER}
+    spack install --reuse ${SPACK_COMPILER}
     spack compiler add $(spack location --install-dir $SPACK_COMPILER)
   fi
 }

templates/common/build_icon.sh

@@ -17,7 +17,7 @@ cd ${WORKDIR} || exit
 load_spack "%spack.init%" "%spack.root%" "%spack.url%" "%spack.branch%" "%spack.externals%" "%spack.compiler%" "%spack.disable_local_config%" "%spack.user_cache_path%" "%spack.user_config_path%"
 
 if [ ! $(rpm -qa | grep bzip2) ]; then
-  spack install bzip2
+  spack install --reuse bzip2
   spack load --first bzip2
 fi
 
@@ -32,7 +32,7 @@ if [ ! -z "$SPACK_BUILD_ICON" ]; then
     spack repo add ${WORKDIR}/proj/spack_repo
   fi
   spack spec $SPACK_BUILD_ICON
-  spack install $SPACK_BUILD_ICON
+  spack install --reuse $SPACK_BUILD_ICON
   #TODO: had some problems with spack load when more than one version is available, adding --first to overcome that
   # although in principle we should not install the model if its already installed.
   spack load --first "icon-nwp@${ICON_VERSION}%${COMPILER}"