Use jemalloc for Linux musl binaries (#42850)

## What changed

- Configure the CLI and app server to use `tikv-jemallocator` on
  `x86_64-unknown-linux-musl` and `aarch64-unknown-linux-musl`.
- Keep the dependency and global allocator selection scoped to those targets.

GitOrigin-RevId: 93c54c90d9acb7e48edffd032cd8ec685a782210

codex-rs/cli/Cargo.toml

@@ -102,6 +102,9 @@ unicode-segmentation = { workspace = true }
 url = { workspace = true }
 which = { workspace = true }
 
+[target.'cfg(all(target_os = "linux", target_env = "musl", any(target_arch = "x86_64", target_arch = "aarch64")))'.dependencies]
+tikv-jemallocator = { workspace = true }
+
 [target.'cfg(target_os = "windows")'.dependencies]
 codex_windows_sandbox = { package = "codex-windows-sandbox", path = "../windows-sandbox-rs" }
 windows-sys = { version = "0.52", features = [

codex-rs/cli/src/main.rs

@@ -46,6 +46,14 @@ use std::path::PathBuf;
 use std::sync::Arc;
 use supports_color::Stream;
 
+#[cfg(all(
+    target_os = "linux",
+    target_env = "musl",
+    any(target_arch = "x86_64", target_arch = "aarch64")
+))]
+#[global_allocator]
+static ALLOCATOR: tikv_jemallocator::Jemalloc = tikv_jemallocator::Jemalloc;
+
 #[cfg(any(target_os = "macos", target_os = "windows"))]
 mod app_cmd;
 mod cloud_config;