ubunutuのdestination.jsonではsdkにRUN --mount=type=bind,target=/swift-sdk,from=aarch64imageとして公式イメージをマウントしたパスをそのまま渡す感じ。

{ "version": 1, "target": "aarch64-unknown-linux-gnu", "toolchain-bin-dir": "/usr/bin", "sdk": "/swift-sdk", "extra-cc-flags": [ "-fPIC", "-v" ], "extra-cpp-flags": [ "-lstdc++", "-v" ], "extra-swiftc-flags": [ "-resource-dir", "/swift-sdk/usr/lib/swift_static", "-v" ] }