Auto merge of #73265 - mark-i-m:mv-std, r=<try>tmp-nightly

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, 92 deletions

diff --git a/src/libstd/sys/windows/cmath.rs b/src/libstd/sys/windows/cmath.rs
deleted file mode 100644
index 1a5421facd0..00000000000
--- a/src/libstd/sys/windows/cmath.rs
+++ /dev/null
@@ -1,92 +0,0 @@
-#![cfg(not(test))]
-
-use libc::{c_double, c_float};
-
-extern "C" {
-    pub fn acos(n: c_double) -> c_double;
-    pub fn asin(n: c_double) -> c_double;
-    pub fn atan(n: c_double) -> c_double;
-    pub fn atan2(a: c_double, b: c_double) -> c_double;
-    pub fn cbrt(n: c_double) -> c_double;
-    pub fn cbrtf(n: c_float) -> c_float;
-    pub fn cosh(n: c_double) -> c_double;
-    pub fn expm1(n: c_double) -> c_double;
-    pub fn expm1f(n: c_float) -> c_float;
-    pub fn fdim(a: c_double, b: c_double) -> c_double;
-    pub fn fdimf(a: c_float, b: c_float) -> c_float;
-    #[cfg_attr(target_env = "msvc", link_name = "_hypot")]
-    pub fn hypot(x: c_double, y: c_double) -> c_double;
-    #[cfg_attr(target_env = "msvc", link_name = "_hypotf")]
-    pub fn hypotf(x: c_float, y: c_float) -> c_float;
-    pub fn log1p(n: c_double) -> c_double;
-    pub fn log1pf(n: c_float) -> c_float;
-    pub fn sinh(n: c_double) -> c_double;
-    pub fn tan(n: c_double) -> c_double;
-    pub fn tanh(n: c_double) -> c_double;
-}
-
-pub use self::shims::*;
-
-#[cfg(not(all(target_env = "msvc", target_arch = "x86")))]
-mod shims {
-    use libc::c_float;
-
-    extern "C" {
-        pub fn acosf(n: c_float) -> c_float;
-        pub fn asinf(n: c_float) -> c_float;
-        pub fn atan2f(a: c_float, b: c_float) -> c_float;
-        pub fn atanf(n: c_float) -> c_float;
-        pub fn coshf(n: c_float) -> c_float;
-        pub fn sinhf(n: c_float) -> c_float;
-        pub fn tanf(n: c_float) -> c_float;
-        pub fn tanhf(n: c_float) -> c_float;
-    }
-}
-
-// On 32-bit x86 MSVC these functions aren't defined, so we just define shims
-// which promote everything fo f64, perform the calculation, and then demote
-// back to f32. While not precisely correct should be "correct enough" for now.
-#[cfg(all(target_env = "msvc", target_arch = "x86"))]
-mod shims {
-    use libc::c_float;
-
-    #[inline]
-    pub unsafe fn acosf(n: c_float) -> c_float {
-        f64::acos(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn asinf(n: c_float) -> c_float {
-        f64::asin(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn atan2f(n: c_float, b: c_float) -> c_float {
-        f64::atan2(n as f64, b as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn atanf(n: c_float) -> c_float {
-        f64::atan(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn coshf(n: c_float) -> c_float {
-        f64::cosh(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn sinhf(n: c_float) -> c_float {
-        f64::sinh(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn tanf(n: c_float) -> c_float {
-        f64::tan(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn tanhf(n: c_float) -> c_float {
-        f64::tanh(n as f64) as c_float
-    }
-}