diff --git a/crypto/compat/arc4random.h b/crypto/compat/arc4random.h
index 8b88e86..9dae794 100644
--- a/crypto/compat/arc4random.h
+++ b/crypto/compat/arc4random.h
@@ -1,3 +1,6 @@
+#ifndef LIBCRYPTOCOMPAT_ARC4RANDOM_H
+#define LIBCRYPTOCOMPAT_ARC4RANDOM_H
+
 #if defined(__linux__)
 #include "arc4random_linux.h"
 
@@ -15,3 +18,4 @@
 
 #endif
 
+#endif