Merge #388

388: add BSD socket layer r=stlankes a=stlankes

The new BSD socket layer depends on hermit-os/kernel#633 and a revised version of `std`. `std` is part of the [rust](/hermitcore/rust/tree/socket) fork. Note: If you use this version, please modify `Cargo.toml`.  [`hermit-abi`](https://github.com/hermitcore/rust/blob/socket/library/std/Cargo.toml#L45) must point to the version of this PR.    

Co-authored-by: Stefan Lankes <slankes@eonerc.rwth-aachen.de>

Author: bors[bot]

hermit-abi/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "hermit-abi"
-version = "0.2.6"
+version = "0.3.0"
 authors = ["Stefan Lankes"]
 license = "MIT OR Apache-2.0"
 readme = "README.md"