Fix lifetime issues with buildgen::builder()
Fix lifetime issues with buildgen::builder()

I switched to the consuming builder pattern, as that seemed the
easiest, and ditched the phantom markers while I was at it.

jdub/rust-bindgen,catdesk/rust-bindgen,jdub/rust-bindgen,rust-lang/rust-bindgen,rust-lang/rust-bindgen,emilio/rust-bindgen,catdesk/rust-bindgen,rust-lang/rust-bindgen,emilio/rust-bindgen,catdesk/rust-bindgen,catdesk/rust-bindgen,emilio/rust-bindgen,rust-lang/rust-bindgen,jdub/rust-bindgen,emilio/rust-bindgen,emilio/rust-bindgen,jdub/rust-bindgen