Auto merge of #73265 - mark-i-m:mv-std, r=Mark-Simulacrum,mark-i-m

mv std libs to library/

This is the first step in refactoring the directory layout of this repository, with further followup steps planned (but not done yet).

Background: currently, all crates are under src/, without nested src directories and with the unconventional `lib*` prefixes (e.g., `src/libcore/lib.rs`). This directory structures is not idiomatic and makes the `src/` directory rather overwhelming. To improve contributor experience and make things a bit more approachable, we are reorganizing the repo a bit.

In this PR, we move the standard libs (basically anything that is "runtime", as opposed to part of the compiler, build system, or one of the tools, etc). The new layout moves these libraries to a new `library/` directory in the root of the repo. Additionally, we remove the `lib*` prefixes and add nested `src/` directories.  The other crates/tools in this repo are not touched. So in summary:

```
library/<crate>/src/*.rs
src/<all the rest>     // unchanged
```

where `<crate>` is:
- core
- alloc
- std
- test
- proc_macro
- panic_abort
- panic_unwind
- profiler_builtins
- term
- unwind
- rtstartup
- backtrace
- rustc-std-workspace-*

There was a lot of discussion about this and a few rounds of compiler team approvals, FCPs, MCPs, and nominations. The original MCP is https://github.com/rust-lang/compiler-team/issues/298. The final approval of the compiler team was given here: https://github.com/rust-lang/rust/pull/73265#issuecomment-659498446.

The name `library` was chosen to complement a later move of the compiler crates to a `compiler/` directory. There was a lot of discussion around adding the nested `src/` directories. Note that this does increase the nesting depth (plausibly important for manual traversal of the tree, e.g., through GitHub's UI or `cd`), but this is deemed to be better as it fits the standard layout of Rust crates throughout most of the ecosystem, though there is some debate about how much this should apply to multi-crate projects. Overall, there seem to be more people in favor of nested `src/` than against.

After this PR, there are no dependencies out of the `library/` directory except on the `build_helper` (or crates.io crates).

1 files changed, 0 insertions, 66 deletions

diff --git a/src/libstd/sys/cloudabi/stdio.rs b/src/libstd/sys/cloudabi/stdio.rs
deleted file mode 100644
index 601563c5b1f..00000000000
--- a/src/libstd/sys/cloudabi/stdio.rs
+++ /dev/null
@@ -1,66 +0,0 @@
-use crate::io;
-use crate::sys::cloudabi::abi;
-
-pub struct Stdin(());
-pub struct Stdout(());
-pub struct Stderr(());
-
-impl Stdin {
-    pub fn new() -> io::Result<Stdin> {
-        Ok(Stdin(()))
-    }
-}
-
-impl io::Read for Stdin {
-    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> {
-        Ok(0)
-    }
-}
-
-impl Stdout {
-    pub fn new() -> io::Result<Stdout> {
-        Ok(Stdout(()))
-    }
-}
-
-impl io::Write for Stdout {
-    fn write(&mut self, _buf: &[u8]) -> io::Result<usize> {
-        Err(io::Error::new(
-            io::ErrorKind::BrokenPipe,
-            "Stdout is not connected to any output in this environment",
-        ))
-    }
-
-    fn flush(&mut self) -> io::Result<()> {
-        Ok(())
-    }
-}
-
-impl Stderr {
-    pub fn new() -> io::Result<Stderr> {
-        Ok(Stderr(()))
-    }
-}
-
-impl io::Write for Stderr {
-    fn write(&mut self, _buf: &[u8]) -> io::Result<usize> {
-        Err(io::Error::new(
-            io::ErrorKind::BrokenPipe,
-            "Stderr is not connected to any output in this environment",
-        ))
-    }
-
-    fn flush(&mut self) -> io::Result<()> {
-        Ok(())
-    }
-}
-
-pub fn is_ebadf(err: &io::Error) -> bool {
-    err.raw_os_error() == Some(abi::errno::BADF as i32)
-}
-
-pub const STDIN_BUF_SIZE: usize = crate::sys_common::io::DEFAULT_BUF_SIZE;
-
-pub fn panic_output() -> Option<impl io::Write> {
-    Stderr::new().ok()
-}