vamp-plugin-sdk: fix cross compilation

pkgs/development/libraries/audio/vamp-plugin-sdk/default.nix

@@ -18,6 +18,10 @@ stdenv.mkDerivation rec {
   buildInputs = [ libsndfile ];
 
   enableParallelBuilding = true;
+  makeFlags = [
+    "AR:=$(AR)"
+    "RANLIB:=$(RANLIB)"
+  ] ++ lib.optional (stdenv.buildPlatform != stdenv.hostPlatform) "-o test";
 
   meta = with lib; {
     description = "Audio processing plugin system for plugins that extract descriptive information from audio data";