ci: Avoid error on macOS native

This avoids "mkdir: /ci_container_base: Read-only file system"

Author: MarcoFalke

.github/workflows/ci.yml

@@ -34,6 +34,7 @@ jobs:
       CI_USE_APT_INSTALL: 'no'
       PACKAGE_MANAGER_INSTALL: 'echo'  # Nothing to do
       FILE_ENV: './ci/test/00_setup_env_mac_native.sh'
+      BASE_ROOT_DIR: ${{ github.workspace }}
 
     steps:
       - name: Checkout

ci/test/00_setup_env.sh

@@ -15,7 +15,7 @@ export BASE_READ_ONLY_DIR
 # The destination root dir inside the container.
 # This folder will also hold any SDKs.
 # This folder only exists on the ci guest and will be a copy of BASE_READ_ONLY_DIR
-export BASE_ROOT_DIR="/ci_container_base"
+export BASE_ROOT_DIR="${BASE_ROOT_DIR:-/ci_container_base}"
 # The depends dir.
 # This folder exists only on the ci guest, and on the ci host as a volume.
 export DEPENDS_DIR=${DEPENDS_DIR:-$BASE_ROOT_DIR/depends}