bmake: test musl build

Since we do some additional patching to make it work with musl, we
should also test that, so we can _keep_ it working.

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

@@ -1,5 +1,6 @@
 { lib, stdenv, fetchurl, fetchpatch
 , getopt, tzdata
+, pkgsMusl # for passthru.tests
 }:
 
 stdenv.mkDerivation rec {
@@ -79,6 +80,10 @@ stdenv.mkDerivation rec {
 
   setupHook = ./setup-hook.sh;
 
+  passthru.tests = {
+    bmakeMusl = pkgsMusl.bmake;
+  };
+
   meta = with lib; {
     description = "Portable version of NetBSD 'make'";
     homepage    = "http://www.crufty.net/help/sjg/bmake.html";