utils/docker-run: mount the download directory if specified

If the user has defined $BR2_DL_DIR in the environment, it would be
nice to have it accessible inside the Docker container, and the
BR2_DL_DIR environment variable set to access it.

This commit does exactly this: it mounts the host $BR2_DL_DIR as /dl
in the container, and sets BR2_DL_DIR=/dl in the container.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[yann.morin.1998@free.fr: use the new mountpoints list]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

utils/docker-run

@@ -35,6 +35,11 @@ if [ "${GIT_DIR}" ]; then
     mountpoints+=( "${GIT_DIR}" )
 fi
 
+if [ "${BR2_DL_DIR}" ]; then
+    mountpoints+=( "${BR2_DL_DIR}" )
+    docker_opts+=( --env BR2_DL_DIR )
+fi
+
 # shellcheck disable=SC2013 # can't use while-read because of the assignment
 for dir in $(printf '%s\n' "${mountpoints[@]}" |LC_ALL=C sort -u); do
     docker_opts+=( --mount "type=bind,src=${dir},dst=${dir}" )