Add support for musl Python toolchain fetches

Cargo.toml

@@ -120,6 +120,7 @@ serde = { version = "1.0.197", features = ["derive"] }
 serde_json = { version = "1.0.114" }
 sha2 = { version = "0.10.8" }
 sys-info = { version = "0.9.1" }
+target-lexicon = {version = "0.12.14" }
 tempfile = { version = "3.9.0" }
 textwrap = { version = "0.16.1" }
 thiserror = { version = "1.0.56" }

crates/uv-toolchain/Cargo.toml

@@ -41,6 +41,7 @@ same-file = { workspace = true }
 schemars = { workspace = true, optional = true }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
+target-lexicon = { workspace = true }
 tempfile = { workspace = true }
 thiserror = { workspace = true }
 tokio-util = { workspace = true, features = ["compat"] }

crates/uv-toolchain/src/platform.rs

@@ -1,7 +1,4 @@
-use std::{
-    fmt::{self},
-    str::FromStr,
-};
+use std::{fmt, str::FromStr};
 use thiserror::Error;
 
 /// All supported operating systems.
@@ -130,10 +127,18 @@ impl Arch {
 
 impl Libc {
     pub(crate) fn from_env() -> Self {
-        // TODO(zanieb): Perform this lookup
         match std::env::consts::OS {
             // Supported platforms.
-            "linux" => Libc::Gnu,
+            "linux" => {
+                let environment = target_lexicon::HOST.environment.into_str();
+                if environment.starts_with("gnu") || environment == "linuxkernel" {
+                    Libc::Gnu
+                } else if environment.starts_with("musl") {
+                    Libc::Musl
+                } else {
+                    Libc::None
+                }
+            }
             "windows" | "macos" => Libc::None,
             // Platforms without explicit support.
             _ => Libc::None,