I'm trying to fix rust-osdev/uefi-rs#104 (comment). Rustfmt needs a new engough syntax to support "efiapi". I tired to do what #3870 did and bump rustc-ap-syntax to version 626.

This caused a very large number of compiler errors. Some of them are caused by small changes like: rust-lang/rust@742ec4b, which are easy enough to fix. However, others errors are caused by changes like rust-lang/rust@c189565 that make a bunch of libsyntax's functionality private.

What should I do here? Should the libsyntax commits be reverted in the main rust-lang/rust repo?

CC: @Centril