add basic IP support in HermitCore

[stlankes]

• add initial version to support sockets within HermitCore
• use TcpStream as test case
• HermitCore uses smoltcp as IP stack for pure Rust applications
• further functionalities (e.g. UDP support) will be added step by step

[rust-highfive]

r? @KodrAus

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[rust-highfive]

The job mingw-check of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

2020-02-23T18:44:19.5735486Z ========================== Starting Command Output ===========================
2020-02-23T18:44:19.5740472Z [command]/bin/bash --noprofile --norc /home/vsts/work/_temp/ddf4fc90-4688-4a04-8819-89d904d1b982.sh
2020-02-23T18:44:19.5740989Z 
2020-02-23T18:44:19.5745203Z ##[section]Finishing: Disable git automatic line ending conversion
2020-02-23T18:44:19.5766209Z ##[section]Starting: Checkout rust-lang/rust@refs/pull/69404/merge to s
2020-02-23T18:44:19.5769651Z Task         : Get sources
2020-02-23T18:44:19.5769999Z Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
2020-02-23T18:44:19.5770315Z Version      : 1.0.0
2020-02-23T18:44:19.5770531Z Author       : Microsoft
---
2020-02-23T18:44:20.5622647Z ##[command]git remote add origin https://github.com/rust-lang/rust
2020-02-23T18:44:20.5628397Z ##[command]git config gc.auto 0
2020-02-23T18:44:20.5659734Z ##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
2020-02-23T18:44:20.5663484Z ##[command]git config --get-all http.proxy
2020-02-23T18:44:20.5670659Z ##[command]git -c http.extraheader="AUTHORIZATION: basic ***" fetch --force --tags --prune --progress --no-recurse-submodules --depth=2 origin +refs/heads/*:refs/remotes/origin/* +refs/pull/69404/merge:refs/remotes/pull/69404/merge
---
2020-02-23T18:47:29.8754254Z   local time: Sun Feb 23 18:47:29 UTC 2020
2020-02-23T18:47:30.0326971Z   network time: Sun, 23 Feb 2020 18:47:30 GMT
2020-02-23T18:47:30.0338352Z == end clock drift check ==
2020-02-23T18:47:30.5533927Z 
2020-02-23T18:47:30.5609132Z ##[error]Bash exited with code '1'.
2020-02-23T18:47:30.5626283Z ##[section]Finishing: Run build
2020-02-23T18:47:30.5676380Z ##[section]Starting: Checkout rust-lang/rust@refs/pull/69404/merge to s
2020-02-23T18:47:30.5681684Z Task         : Get sources
2020-02-23T18:47:30.5682074Z Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
2020-02-23T18:47:30.5682450Z Version      : 1.0.0
2020-02-23T18:47:30.5682700Z Author       : Microsoft
2020-02-23T18:47:30.5682700Z Author       : Microsoft
2020-02-23T18:47:30.5683298Z Help         : [More Information](https://go.microsoft.com/fwlink/?LinkId=798199)
2020-02-23T18:47:30.5683778Z ==============================================================================
2020-02-23T18:47:30.9212658Z Cleaning any cached credential from repository: rust-lang/rust (GitHub)
2020-02-23T18:47:30.9256404Z ##[section]Finishing: Checkout rust-lang/rust@refs/pull/69404/merge to s
2020-02-23T18:47:30.9338449Z Cleaning up task key
2020-02-23T18:47:30.9339774Z Start cleaning up orphan processes.
2020-02-23T18:47:30.9500257Z Terminate orphan process: pid (4525) (python)
2020-02-23T18:47:30.9622935Z ##[section]Finishing: Finalize Job

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[stlankes]

r? @alexcrichton

[alexcrichton]

Thanks for the ping but I unfortunately don't have time to help maintain all the targets of libstd nowadays myself.

[stlankes]

No problem!

[JohnTitor]

One nit: we have "no merge policy" here, recommend not including merge commits on PR: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#pull-requests

[stlankes]

Oh, yes. I will fix it

[stlankes]

I close it and resubmit it after revising my code