diff --git a/_constraints b/_constraints
new file mode 100644
index 0000000..bd98885
--- /dev/null
+++ b/_constraints
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<constraints>
+  <overwrite>
+    <conditions>
+      <arch>x86_64</arch>
+    </conditions>
+    <hardware>
+      <cpu>
+        <flag>pclmulqdq</flag>
+        <flag>sse2</flag>
+        <flag>sse4.1</flag>
+      </cpu>
+    </hardware>
+  </overwrite>
+</constraints>