ensure dtrace stderr is piped through

CHANGES.md

@@ -2,7 +2,9 @@
 
 ## bunyan 0.16.2 (not yet released)
 
-(nothing yet)
+- Ensure that stderr from the dtrace child process (when using `bunyan -p PID`)
+  gets through. The `pipe` usage wasn't working on SmartOS. This is important
+  to show the user if they need to 'sudo'.
 
 
 ## bunyan 0.16.1

bin/bunyan

@@ -910,7 +910,10 @@ function processPid(opts, stylize, callback) {
   var dtrace = spawn(argv[0], argv.slice(1));
   child = dtrace; // intentionall global
 
-  dtrace.stderr.pipe(process.stderr);
+  dtrace.stderr.setEncoding('utf8');
+  dtrace.stderr.on('data', function (chunk) {
+    process.stderr.write(chunk);
+  });
 
   dtrace.stdout.setEncoding('utf8');
   dtrace.stdout.on('data', function (chunk) {