auto merge of #5063 : pcwalton/rust/plussing, r=pcwalton

diff --cc src/libcore/at_vec.rs
Simple merge

diff --cc src/libcore/pipes.rs
Simple merge

diff --cc src/libcore/private.rs
Simple merge

diff --cc src/libcore/private/global.rs
Simple merge

diff --cc src/libcore/vec.rs
Simple merge