Add built-in support for *-linux-none targets (#618)

Author: newpavlov

.github/workflows/build.yml

@@ -94,6 +94,7 @@ jobs:
           x86_64-wrs-vxworks,
           x86_64-unknown-dragonfly,
           x86_64-unknown-haiku,
+          x86_64-unknown-linux-none,
           # TODO: once libc support for cygwin is released
           # https://github.com/rust-lang/libc/pull/4308
           # x86_64-pc-cygwin,

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `.cargo/config.toml` example in the crate-level docs [#591]
 - `getrandom_test_linux_without_fallback` configuration flag to test that file fallback
   is not triggered in the `linux_android_with_fallback` backend [#605]
+- Built-in support for `*-linux-none` targets [#618]
 - Cygwin support [#626]
 
 ### Changed
@@ -38,6 +39,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [#605]: https://github.com/rust-random/getrandom/pull/605
 [#610]: https://github.com/rust-random/getrandom/pull/610
 [#614]: https://github.com/rust-random/getrandom/pull/614
+[#618]: https://github.com/rust-random/getrandom/pull/618
 [#626]: https://github.com/rust-random/getrandom/pull/626
 [#627]: https://github.com/rust-random/getrandom/pull/627
 [`raw-dylib`]: https://doc.rust-lang.org/reference/items/external-blocks.html?highlight=link#dylib-versus-raw-dylib

Cargo.toml

@@ -31,7 +31,7 @@ compiler_builtins = { version = "0.1", optional = true }
 core = { version = "1.0", optional = true, package = "rustc-std-workspace-core" }
 
 # getrandom / linux_android_with_fallback
-[target.'cfg(all(any(target_os = "linux", target_os = "android"), not(any(getrandom_backend = "custom", getrandom_backend = "linux_raw", getrandom_backend = "rdrand", getrandom_backend = "rndr"))))'.dependencies]
+[target.'cfg(all(any(target_os = "linux", target_os = "android"), not(any(all(target_os = "linux", target_env = ""), getrandom_backend = "custom", getrandom_backend = "linux_raw", getrandom_backend = "rdrand", getrandom_backend = "rndr"))))'.dependencies]
 libc = { version = "0.2.154", default-features = false }
 
 # apple-other

src/backends.rs

@@ -38,6 +38,9 @@ cfg_if! {
                 );
             }
         }
+    } else if #[cfg(all(target_os = "linux", target_env = ""))] {
+        mod linux_raw;
+        pub use linux_raw::*;
     } else if #[cfg(target_os = "espidf")] {
         mod esp_idf;
         pub use esp_idf::*;