Tested with https://github.com/rust-lang/rust-bindgen v0.47
Test fails with v0.48 and v0.49 (2019-04-28).
Related issue: rust-lang/rust-bindgen#1498
However, similar problems still occur, so we fix to use bindgen 0.47.
Tested with https://github.com/rust-lang/rust-bindgen v0.47
Test fails with v0.48 and v0.49 (2019-04-28).
Related issue: rust-lang/rust-bindgen#1498
However, similar problems still occur, so we fix to use bindgen 0.47.