tracking issue: upstream bindgen issues affecting us

[jschwe]

• opaque types should not autoderive copy and clone
• --no-copy actually prevents derivation of copy AND clone. Currently no API to only derive clone, but not copy.
• opaque types declared in different header files are incompatible in Rust (could be argued that this is not a bindgen issue）
• structs containing a pointer should not autoderive copy

Todo: add links to the upstream issues.