added stderr

python/mppy.py

@@ -59,11 +59,18 @@ class Mpp:
                         break
                     if stdout:
                         print(stdout.decode('utf-8').strip('\n'))
-
+            rc = process.poll()
+            if rc != 0:
+                while True:
+                    stderr = process.stderr.readline()
+                    if stderr == b'' and process.poll() is not None:
+                        break
+                    if stderr:
+                        print(stderr.decode('utf-8').strip('\n'))
             process.wait()
             process.stdout.close()
             process.stderr.close()
-            return process.poll()
+            return rc
 
     def create_working_dir(self):
         if not os.path.isdir(self.PROJECT_BUILD_DIR):