message: Make Snappy header available
  This is going to be useful for the tensor database I'm working on.
diff: @@ -1398,6 +1398,7 @@ LIB_INTERNAL_PUBLIC_HEADERS = tf_additional_lib_hdrs() + [
  "platform/platform.h",
  "platform/protobuf_internal.h",
  "platform/setround.h",
  + "platform/snappy.h",
  "platform/tensor_coding.h",
  "platform/tracing.h",
  ]
  @@ -2257,7 +2258,6 @@ cc_library(
  "lib/io/block_builder.h",
  "lib/io/format.h",
  "lib/random/philox_random_test_utils.h",
  - "platform/snappy.h",
  ],
  deps = [
  ":lib",
  