Looks like this function changed upstream, so it needs to be adjusted
for when used by libstd.

This PR reverts rust-lang#48065, which aimed to optimize `Vec::retain` by
making use of `Vec::drain_filter`. Unfortunately at that time,
`drain_filter` was unsound.

The soundness hole in `Vec::drain_filter` was fixed in rust-lang#61224 by
guaranteeing that cleanup logic runs via a nested `Drop`, even in
the event of a panic. Implementing this nested drop affects codegen
(apparently?) and results in slower code.

Fixes rust-lang#65970

…ly, r=alexcrichton

Remove i686-unknown-dragonfly target

DragonFly BSD removed support for i386 a while ago. It only supports x86_64 right now.

…lan-DPC

Fix signature of `__wasilibc_find_relpath`

Looks like this function changed upstream, so it needs to be adjusted
for when used by libstd.

Fix example code of OpenOptions::open

The example didn't set the access mode flag, which resulted in an `Err(InvalidInput)`.

r? @steveklabnik

Do not ICE on unnamed future

Fix rust-lang#67252.

Restore original implementation of Vec::retain

This PR reverts rust-lang#48065, which aimed to optimize `Vec::retain` by making use of `Vec::drain_filter`. Unfortunately at that time, `drain_filter` was unsound.

The soundness hole in `Vec::drain_filter` was fixed in rust-lang#61224 by guaranteeing that cleanup logic runs via a nested `Drop`, even in the event of a panic. Implementing this nested drop affects codegen (apparently?) and results in slower code.

Fixes rust-lang#65970

Doc typo