gen: Refactor attribute logic and add unsafe_no_drop_flag
gen: Refactor attribute logic and add unsafe_no_drop_flag

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