Fix gc-native-roots failures on ARM Linux and macOS

.github/workflows/gc-native-roots.yml

@@ -673,7 +673,9 @@ jobs:
           export PERRY_RUNTIME_DIR="$PWD/target/perry-dev"
           export PERRY_NO_AUTO_OPTIMIZE=1
           unset PERRY_LLVM_OPT PERRY_LLVM_CLANG
-          export LLVM_SYS_221_PREFIX="$(brew --prefix llvm)"
+          # Keep LLVM_SYS_221_PREFIX from setup-llvm22. The stock-toolchain
+          # assertion removes the external opt/clang overrides; the in-process
+          # backend itself still has to link the LLVM 22 ABI used by llvm-sys.
           export RUSTFLAGS="-C force-frame-pointers=yes -C force-unwind-tables=yes"
           cargo build --profile perry-dev -p perry -p perry-runtime-static \
             -p perry-stdlib-static --features perry-codegen/llvm-inprocess

changelog.d/9920-gc-native-roots-platforms.md

@@ -0,0 +1,5 @@
+### Fixed
+
+- Restore the scheduled native-roots gate on ARM Linux and macOS by handling
+  libyaml's target-specific `c_char` signedness and retaining its configured
+  LLVM 22 prefix for the in-process backend.

crates/perry-runtime/src/bun_compat/cli_utils.rs

@@ -947,7 +947,7 @@ fn yaml_parse(input: f64) -> f64 {
                 let problem = if parser.problem.is_null() {
                     "invalid YAML".to_string()
                 } else {
-                    std::ffi::CStr::from_ptr(parser.problem)
+                    std::ffi::CStr::from_ptr(parser.problem.cast::<std::ffi::c_char>())
                         .to_string_lossy()
                         .into_owned()
                 };