Add a --recursive option duneci-install-module

This is needed for Dune modules that use git submodules
to initialized the submodules and potentially even their
submodules.

base-common/duneci-install-module

@@ -9,6 +9,7 @@ usage() {
     echo >&2
     echo "options:" >&2
     echo "  -b <branch>, --branch <branch>: Install branch <branch> of the module." >&2
+    echo "  -r, --recursive: Clone the git repository with --recursive (for git submodules)." >&2
     echo >&2
     echo "environment variables:" >&2
     echo "  DUNECI_BRANCH:" >&2
@@ -26,6 +27,7 @@ fi
 
 
 branch="${DUNECI_BRANCH:-}"
+recursive=0
 
 while :; do
     case "${1}" in
@@ -33,6 +35,10 @@ while :; do
             branch="${2}"
             shift 2
             ;;
+        -r|--recursive)
+            recursive=1
+            shift 1
+            ;;
         *)
             break
             ;;
@@ -49,10 +55,13 @@ if [[ -d "${module}" ]]; then
     exit 1
 fi
 
-git_clone_opts=(--depth=1 --no-single-branch)
+git_clone_opts=(--depth=1 --no-single-branch "${recursive}")
 if [[ -n "${branch}" ]]; then
     git_clone_opts+=(-b "${branch}")
 fi
+if [[ ${recursive} ]]; then
+    git_clone_opts+=("--recursive")
+fi
 
 git clone "${git_clone_opts[@]}" "${repo}"
 if [[ "${DUNECI_BRANCH_AUTO:-1}" = "1" && -n "${CI_BUILD_REF_NAME:-}" ]]; then