meson: Add dist script to vendor cargo dependencies for offline builds

build-aux/dist-vendor.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+export DIST="$1"
+export SOURCE_ROOT="$2"
+
+cd "$SOURCE_ROOT"
+mkdir "$DIST"/.cargo
+cargo vendor > $DIST/.cargo/config
+# Move vendor into dist tarball directory
+mv vendor "$DIST"