Log item for which layout retrieval fails

[mohe2015]

Related https://github.com/rust-lang/rust-bindgen/issues/1768, https://github.com/ghpr-asia/wsdf/issues/18

I think this would at least make analyzing this failure easier and based on the wsdf issue it seems that in some cases including another file also helps fixing this.

[aleb]

Using unwrap_or_else leaves the impression that a value might be returned, but the block always panics. How about the change made in the https://github.com/ghpr-asia/wsdf/issues/18 issue you linked:

let Some(layout) = layout else { panic... };

BTW, if anybody else is interested, the item is already logged at the very start of the method and the debug log can be enabled by setting the env var: RUST_LOG=debug

        debug!("<CompInfo as CodeGenerator>::codegen: item = {:?}", item);