message: Make `pyx_library` in default/build_config.bzl compatible with `pyx_library` in google/build_config.bzl.
diff: @@ -34,6 +34,7 @@ def pyx_library(
  py_deps = [],
  srcs = [],
  testonly = None,
  + srcs_version = "PY2AND3",
  **kwargs):
  """Compiles a group of .pyx / .pxd / .py files.
  @@ -97,7 +98,7 @@ def pyx_library(
  name = name,
  srcs = py_srcs,
  deps = py_deps,
  - srcs_version = "PY2AND3",
  + srcs_version = srcs_version,
  data = shared_objects,
  testonly = testonly,
  **kwargs
  