ebpf: run clippy with target=bpf

This build warnings from integration tests and makes `aya-ebpf`'s build
script stricter.

aya-log-common/src/lib.rs

@@ -1,3 +1,7 @@
+#![cfg_attr(
+    target_arch = "bpf",
+    expect(unused_crate_dependencies, reason = "compiler_builtins")
+)]
 #![no_std]
 
 use core::{

clippy.sh

@@ -2,6 +2,15 @@
 
 set -eux
 
+cargo +nightly hack clippy \
+  --target bpfel-unknown-none -Zbuild-std=core \
+  --package aya-ebpf-bindings \
+  --package aya-ebpf \
+  --package aya-log-ebpf \
+  --package integration-ebpf \
+  --feature-powerset \
+  -- --deny warnings
+
 # `-C panic=abort` because "unwinding panics are not supported without std"; integration-ebpf
 # contains `#[no_std]` binaries.
 # 
@@ -11,4 +20,9 @@ set -eux
 # unwinding behavior.
 # 
 # `+nightly` because "the option `Z` is only accepted on the nightly compiler".
-cargo +nightly hack clippy "$@" --all-targets --feature-powerset -- --deny warnings -C panic=abort -Zpanic_abort_tests
+cargo +nightly hack clippy "$@" \
+  --all-targets \
+  --feature-powerset \
+  -- --deny warnings \
+  -C panic=abort \
+  -Zpanic_abort_tests

ebpf/aya-ebpf-bindings/src/lib.rs

@@ -1,3 +1,7 @@
+#![cfg_attr(
+    target_arch = "bpf",
+    expect(unused_crate_dependencies, reason = "compiler_builtins")
+)]
 #![expect(
     clippy::all,
     clippy::cast_lossless,

ebpf/aya-ebpf/build.rs

@@ -1,18 +1,7 @@
-use std::env;
-
 fn main() {
-    check_rust_version();
     println!("cargo:rerun-if-env-changed=CARGO_CFG_BPF_TARGET_ARCH");
-    if let Ok(arch) = env::var("CARGO_CFG_BPF_TARGET_ARCH") {
-        println!("cargo:rustc-cfg=bpf_target_arch=\"{arch}\"");
-    } else {
-        let arch = env::var("HOST").unwrap();
-        let mut arch = arch.split_once('-').map_or(&*arch, |x| x.0);
-        if arch.starts_with("riscv64") {
-            arch = "riscv64";
-        }
-        println!("cargo:rustc-cfg=bpf_target_arch=\"{arch}\"");
-    }
+    println!("cargo:rerun-if-env-changed=HOST");
+
     print!("cargo::rustc-check-cfg=cfg(bpf_target_arch, values(");
     for arch in [
         "aarch64",
@@ -28,7 +17,20 @@ fn main() {
     }
     println!("))");
 
+    if let Some(arch) = std::env::var_os("CARGO_CFG_BPF_TARGET_ARCH") {
+        let arch = arch.to_str().unwrap();
+        println!("cargo:rustc-cfg=bpf_target_arch=\"{arch}\"");
+    } else if let Some(host) = std::env::var_os("HOST") {
+        let host = host.to_str().unwrap();
+        let mut arch = host.split_once('-').map_or(host, |(arch, _rest)| arch);
+        if arch.starts_with("riscv64") {
+            arch = "riscv64";
+        }
+        println!("cargo:rustc-cfg=bpf_target_arch=\"{arch}\"");
+    }
+
     println!("cargo::rustc-check-cfg=cfg(generic_const_exprs)");
+    check_rust_version();
 }
 
 #[rustversion::nightly]

ebpf/aya-ebpf/src/lib.rs

@@ -8,13 +8,18 @@
     html_logo_url = "https://aya-rs.dev/assets/images/crabby.svg",
     html_favicon_url = "https://aya-rs.dev/assets/images/crabby.svg"
 )]
-// TODO(https://github.com/rust-lang/rust/issues/141492): reenable this.
 #![cfg_attr(
     generic_const_exprs,
     expect(incomplete_features),
+    expect(unstable_features),
     feature(generic_const_exprs)
 )]
-#![cfg_attr(target_arch = "bpf", feature(asm_experimental_arch))]
+#![cfg_attr(
+    target_arch = "bpf",
+    expect(unused_crate_dependencies, reason = "compiler_builtins"),
+    expect(unstable_features),
+    feature(asm_experimental_arch)
+)]
 #![warn(clippy::cast_lossless, clippy::cast_sign_loss)]
 #![no_std]
 
@@ -65,7 +70,6 @@ pub trait EbpfContext {
     }
 }
 
-#[cfg_attr(target_arch = "bpf", expect(clippy::missing_safety_doc))]
 mod intrinsics {
     use super::cty::c_int;
 

ebpf/aya-log-ebpf/Cargo.toml

@@ -17,6 +17,3 @@ workspace = true
 aya-ebpf = { version = "^0.1.1", path = "../aya-ebpf" }
 aya-log-common = { version = "^0.1.15", path = "../../aya-log-common" }
 aya-log-ebpf-macros = { version = "^0.1.0", path = "../../aya-log-ebpf-macros" }
-
-[lib]
-path = "src/lib.rs"

ebpf/aya-log-ebpf/src/lib.rs

@@ -1,3 +1,7 @@
+#![cfg_attr(
+    target_arch = "bpf",
+    expect(unused_crate_dependencies, reason = "compiler_builtins")
+)]
 #![no_std]
 #![warn(clippy::cast_lossless, clippy::cast_sign_loss)]