v0.3.5

Changes in 0.3.5:

Support C-unwind ABI

Adds support for extern "C-unwind" ABI through #[unwind_abi] attribute and unwind_abi_default/unwind_abi_ext feature flags:

• unwind_abi_default will default all functions to support unwinding, which can be overridden with #[no_unwind_abi] attribute.
• unwind_abi_ext will add #[unwind_abi] to all functions in the builtin ext system.

Add CWaker

Exposes CWaker as a static stable ABI waker type.