Match the C binding's target arch detection with the root crate's

1 files changed, 12 insertions, 4 deletions

diff --git a/c/blake3_c_rust_bindings/build.rs b/c/blake3_c_rust_bindings/build.rs
index d5dc47a..98f8396 100644
--- a/c/blake3_c_rust_bindings/build.rs
+++ b/c/blake3_c_rust_bindings/build.rs
@@ -22,6 +22,10 @@ fn is_armv7() -> bool {
     target_components()[0] == "armv7"
 }
 
+fn is_aarch64() -> bool {
+    target_components()[0] == "aarch64"
+}
+
 // Windows targets may be using the MSVC toolchain or the GNU toolchain. The
 // right compiler flags to use depend on the toolchain. (And we don't want to
 // use flag_if_supported, because we don't want features to be silently
@@ -148,10 +152,14 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         avx512_build.compile("blake3_avx512");
     }
 
-    // We only build NEON code here if 1) it's requested and 2) the root crate
-    // is not already building it. The only time this will really happen is if
-    // you build this crate by hand with the "neon" feature for some reason.
-    if defined("CARGO_FEATURE_NEON") {
+    // We only build NEON code here if
+    // 1) it's requested
+    // and 2) the root crate is not already building it.
+    // The only time this will really happen is if you build this
+    // crate by hand with the "neon" feature for some reason.
+    //
+    // In addition, 3) if the target is aarch64, NEON is on by default.
+    if defined("CARGO_FEATURE_NEON") || is_aarch64() {
         let mut neon_build = new_build();
         neon_build.file(c_dir_path("blake3_neon.c"));
         // ARMv7 platforms that support NEON generally need the following