Remove feature rustc-build-sysroot

Author: tamird

.github/workflows/ci.yml

@@ -187,15 +187,13 @@ jobs:
       #
       # `RUSTC_BOOTSTRAP` is needed to use `rustc-build-sysroot` on stable Rust.
       - name: Test (sysroot built on demand)
-        env:
-          RUSTC_BOOTSTRAP: 1
         run: |
-          cargo hack test --feature-powerset \
+          RUSTC_BOOTSTRAP=1 cargo hack test --feature-powerset \
             --exclude-features ${{ matrix.exclude-features }} \
-            --features ${{ env.LLVM_FEATURES }},rustc-build-sysroot
+            --features ${{ env.LLVM_FEATURES }}
 
       # To make things easier for package maintainers, the step of building a
-      # custom sysroot can be skipped by setting the `BPF_SYSROOT_SKIP`
+      # custom sysroot can be skipped by setting the `BPFEL_SYSROOT_DIR`
       # environment variable to the path of the prebuilt BPF sysroot.
       #
       # Test this configuration by prebuilding the BPF standard library
@@ -214,10 +212,8 @@ jobs:
             --sysroot-dir "$BPFEL_SYSROOT_DIR" \
             --target bpfel-unknown-none
 
-          # Omit `rustc-build-sysroot` feature to test the prebuilt sysroot.
-          # Omit `default` because it includes `rustc-build-sysroot`.
           BPFEL_SYSROOT_DIR="$BPFEL_SYSROOT_DIR" cargo hack test --feature-powerset \
-            --exclude-features ${{ matrix.exclude-features }},default,rustc-build-sysroot \
+            --exclude-features ${{ matrix.exclude-features }} \
             --features ${{ env.LLVM_FEATURES }}
 
       - uses: actions/checkout@v5

Cargo.toml

@@ -69,9 +69,7 @@ rust-llvm-21 = [
 default = [
     "llvm-21",
     "rust-llvm-21",
-    "rustc-build-sysroot",
 ]
-rustc-build-sysroot = []
 
 [workspace]
 members = ["xtask"]

tests/tests.rs

@@ -128,11 +128,9 @@ fn compile_test() {
     let root_dir = env::var_os("CARGO_MANIFEST_DIR")
         .expect("could not determine the root directory of the project");
     let root_dir = Path::new(&root_dir);
-    let bpf_sysroot = env::var_os("BPFEL_SYSROOT_DIR");
-    let bpf_sysroot = if !cfg!(feature = "rustc-build-sysroot") {
-        PathBuf::from(bpf_sysroot.expect("BPFEL_SYSROOT_DIR is not set"))
+    let bpf_sysroot = if let Some(bpf_sysroot) = env::var_os("BPFEL_SYSROOT_DIR") {
+        PathBuf::from(bpf_sysroot)
     } else {
-        assert_eq!(bpf_sysroot, None);
         let rustc = Command::new(env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc")));
         let rustc_src = rustc_build_sysroot::rustc_sysroot_src(rustc)
             .expect("could not determine sysroot source directory");