Modify tensorflow-sys/src/lib.rs to be bindgen generated

[nbigaouette-eai]

This MR gets rid of the hand-written tensorflow-sys/src/lib.rs file, and replaces it with two files:

1. tensorflow-sys/src/bindgen.rs is the result of bindgen --blacklist-type max_align_t /usr/include/tensorflow/c_api.h > tensorflow-sys/src/bindgen.rs;
2. tensorflow-sys/src/lib.rs simply include!() the generated wrapper, adding some #![allow(...)] and re-exporting the enum values.

I've added the option --blacklist-type max_align_t to bindgen so that the automatically generated unit tests don't fail:

 Running `/home/nbigaouette/projects/agents/tensorflow_rust.git/target/debug/deps/tensorflow_sys-b18d6c19e08d67bd`
running 5 tests
test bindgen_test_layout_TF_AttrMetadata ... ok
test bindgen_test_layout_TF_Buffer ... ok
test bindgen_test_layout_TF_Output ... ok
test bindgen_test_layout_TF_Input ... ok
test bindgen_test_layout_max_align_t ... FAILED
failures:
---- bindgen_test_layout_max_align_t stdout ----
thread 'bindgen_test_layout_max_align_t' panicked at 'assertion failed: `(left == right)` (left: `24`, right: `32`): Size of: max_align_t', src/bindgen.rs:82
note: Run with `RUST_BACKTRACE=1` for a backtrace.
failures:
bindgen_test_layout_max_align_t
test result: FAILED. 4 passed; 1 failed; 0 ignored; 0 measured
error: test failed

See rust-lang/rust-bindgen#550 for the bindgen issue about this unit test.

Should close issue #57.

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[nbigaouette-eai]

I signed it!

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CLAs look good, thanks!

[nbigaouette]

The CI failure is due to tensorflow failing to build and not this MR.

Server finished RPC without an explicit exit code
thread 'main' panicked at 'failed to execute "bazel" "build" "--jobs=2" "--compilation_mode=opt" "--copt=-march=native" "tensorflow:libtensorflow.so"', tensorflow-sys/build.rs:101
note: Run with `RUST_BACKTRACE=1` for a backtrace.

See similar issues in the main tensorflow repository:

• Installation from Source Error: "Server finished RPC without an explicit exit code" tensorflow#6678
• Server finished RPC without an explicit exit code -bash: Server: command not found when use bazel build tensorflow tensorflow#6572

MR #65 could aleviate this problem by using a pre-built binary for tensoflow. This would help a lot!

[adamcrume]

Could you add a script for running bindgen?

[adamcrume]

Thanks!

[daschl]

I think this is a great middle ground between hand-generating the API and forcing couple of compile time dependencies on the user :)