openbsd npm install fix

npm_openbsd

diff --git a/lib/utils/tar.js b/lib/utils/tar.js
index 8c5bf94..ffa4ac1 100644
--- a/lib/utils/tar.js
+++ b/lib/utils/tar.js
@@ -167,11 +167,18 @@ function gunzTarPerm (tarball, tmp, dMode, fMode, uid, gid, cb) {
   //console.error(npm.config.get("gzipbin")+" --decompress --stdout "
   //  +tarball+" | "+npm.config.get("tar")+" -mvxpf - --no-same-owner -C "
   //  +tmp)
+  var os = require("os");
+  var opts = [ "-mvxpf", "-", "--no-same-owner", "-C", tmp];
+
+  if ( os.type() === 'OpenBSD' ) {
+         opts = [ "-mvxpf", "-", "-C", tmp];
+  }
+
   pipe( spawn( npm.config.get("gzipbin")
              , ["--decompress", "--stdout", tarball]
              , process.env, false )
       , spawn( npm.config.get("tar")
-             , ["-mvxpf", "-", "--no-same-owner", "-C", tmp]
+             , opts
              , process.env, false )
       , function (er) {
           // if we're not doing ownership management,