unbound: fix cross-compilation

Due to a check in make-derivation.nix (https://github.com/nixos/nixpkgs/blob/e4f449ab51a283676d3b520c3dbaa3eafa5025b4/pkgs/stdenv/generic/make-derivation.nix#L288),
`nativeCheckInputs` is not used. This causes cross-compilation for
unbound to fail due to the programs in `bison` not being available.

pkgs/by-name/un/unbound/package.nix

@@ -67,7 +67,7 @@ stdenv.mkDerivation (finalAttrs: {
   nativeBuildInputs =
     lib.optionals withMakeWrapper [ makeWrapper ]
     ++ lib.optionals withDNSTAP [ protobufc ]
-    ++ [ pkg-config flex ]
+    ++ [ pkg-config flex bison ]
     ++ lib.optionals withPythonModule [ swig ];
 
   buildInputs = [ openssl nettle expat libevent ]
@@ -121,8 +121,6 @@ stdenv.mkDerivation (finalAttrs: {
     sed -E '/CONFCMDLINE/ s;${storeDir}/[a-z0-9]{32}-;${storeDir}/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-;g' -i config.h
   '';
 
-  nativeCheckInputs = [ bison ];
-
   doCheck = true;
 
   postPatch = lib.optionalString withPythonModule ''