bmake: add setupHook

With this change,

    nativeBuildInputs = [ bmake ];

will cause bmake to be used instead of GNU make, but with the usual
stdenv API.  Packages using bmake will no longer need to implement
their own {build,check,dist}Phase.

pkgs/development/tools/build-managers/bmake/default.nix

@@ -18,6 +18,8 @@ stdenv.mkDerivation rec {
     ./fix-unexport-env-test.patch
   ];
 
+  setupHook = ./setup-hook.sh;
+
   meta = with lib; {
     description = "Portable version of NetBSD 'make'";
     homepage    = "http://www.crufty.net/help/sjg/bmake.html";