diff --git a/pkgs/tools/security/rng-tools/default.nix b/pkgs/tools/security/rng-tools/default.nix
index 1885940e7f3..d2326c7e8c3 100644
--- a/pkgs/tools/security/rng-tools/default.nix
+++ b/pkgs/tools/security/rng-tools/default.nix
@@ -9,6 +9,9 @@ stdenv.mkDerivation rec {
     sha256 = "13h7lc8wl9khhvkr0i3bl5j9bapf8anhqis1lcnwxg1vc2v058b0";
   };
 
+  # For cross-compilation
+  makeFlags = [ "AR:=$(AR)" ];
+
   meta = {
     description = "A random number generator daemon";