I and some other folks in the Rust audio community have put together some low-level bindings for the CLAP API: https://github.com/glowcoil/clap-sys

They're relatively straightforward due to the fact that CLAP is a simple, pure-C ABI, and there are already some fully functional plugins making use of them (e.g. https://github.com/robbert-vdh/nih-plug).