auto merge of #9630 : blake2-ppc/rust/de-at-smaller, r=huonw

This is mostly an incremental change, picking off some uses of
@- or @mut-pointers that can be replaced by references.

Almost all of the builder functions in trans::build are updated,
mostly using `&Block` arguments instead of `@mut Block`.

diff --cc src/librustc/middle/resolve.rs
Simple merge

diff --cc src/librustc/middle/trans/base.rs
Simple merge