message: Extract Bazel version from source tree in PyPI build script.
diff: @@ -32,8 +32,10 @@ PYTHON_VERSIONS["3.8"]="cp38-cp38"
  PYTHON_VERSIONS["3.9"]="cp39-cp39"
  readonly -A PYTHON_VERSIONS
  -readonly BAZEL_VERSION='4.2.2'
  -readonly PROTOC_VERSION='3.19.3'
  +readonly TINK_SRC_PATH="/tmp/tink"
  +
  +readonly BAZEL_VERSION="$(cat "${TINK_SRC_PATH}/python/.bazelversion")"
  +readonly PROTOC_VERSION="3.19.3"
  # Get dependencies which are needed for building Tink.
  @@ -48,7 +50,7 @@ curl -OL "https://github.com/protocolbuffers/protobuf/releases/download/v${PROTO
  unzip -o "${PROTOC_ZIP}" -d /usr/local bin/protoc
  # Setup required for Tink.
  -export TINK_PYTHON_SETUPTOOLS_OVERRIDE_BASE_PATH="/tmp/tink"
  +export TINK_PYTHON_SETUPTOOLS_OVERRIDE_BASE_PATH="${TINK_SRC_PATH}"
  # Workaround for grpc which expects a python2 installation, which is not present
  # in the manylinux2014 container. Cannot be an empty string, otherwise Bazel
  