Trying to build dev-util/cargo-0.17.0 fails for me when trying to download 'advapi32-sys-0.2.0.crate'. Trying to download it manually shows that 'https://crates.io/api/v1/crates/advapi32-sys/0.2.0/download' is not a valid URL. I assume there's a new download url that is needed (for all crates, not just this one, which happens to be the first on the list). Thanks!
Nevermind. The crates urls weren't working from behind a corporate http proxy when using tnftp as the download manager for portage. (Yes, that's an obscure mix.) After switching to wget, everything works fine. Also, for whatever reason, the crates can't be downloaded w/ the crates.io API using a browser. (Something about the "accept" header?) *shrug*