Rework AVX/AVX2 detection again

perf/build.rs

@@ -0,0 +1,11 @@
+fn main() {
+    #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+    {
+        if is_x86_feature_detected!("avx") {
+            println!("cargo:rustc-cfg=build_target_feature_avx");
+        }
+        if is_x86_feature_detected!("avx2") {
+            println!("cargo:rustc-cfg=build_target_feature_avx2");
+        }
+    }
+}