circus: fix build with Python 3.7.0

Python 3.7.0 makes 'async' a reserved keyword, but circus uses it as a
method argument. This commit adds a patch to the circus package, which
has been submitted upstream, to resolve this issue.

Fixes:

  http://autobuild.buildroot.net/results/8122a00644810722b827cd5e0b90181996dc5657/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/circus/0001-circus-tests-rename-async-argument-of-_create_circus.patch

@@ -0,0 +1,97 @@
+From 7fd0495cf3520508fb1cca301ad3d792b56b5656 Mon Sep 17 00:00:00 2001
+From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
+Date: Sat, 8 Sep 2018 22:24:24 +0200
+Subject: [PATCH] circus/tests: rename async argument of _create_circus() to
+ use_async
+
+In Python 3.7.0, 'async' is now a reserved keyword of the language, so
+it cannot be used as an method argument name. When used, it causes the
+following byte-compilation failure:
+
+Traceback (most recent call last):
+  File "/home/thomas/projets/buildroot/output/host/lib/python3.7/py_compile.py", line 136, in compile
+    _optimize=optimize)
+  File "<frozen importlib._bootstrap_external>", line 763, in source_to_code
+  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
+  File "usr/lib/python3.7/site-packages/circus/tests/support.py", line 210
+    debug=debug, async=True, **kw)
+                     ^
+SyntaxError: invalid syntax
+
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
+Upstream-status: https://github.com/circus-tent/circus/pull/1079
+---
+ circus/tests/support.py      | 6 +++---
+ circus/tests/test_client.py  | 2 +-
+ circus/tests/test_watcher.py | 4 ++--
+ 3 files changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/circus/tests/support.py b/circus/tests/support.py
+index 38964cc..794a9c7 100644
+--- a/circus/tests/support.py
++++ b/circus/tests/support.py
+@@ -217,7 +217,7 @@ class TestCircus(AsyncTestCase):
+                       stdout_stream=None, debug=True, **kw):
+         testfile, arbiter = self._create_circus(
+             cmd, stdout_stream=stdout_stream,
+-            debug=debug, async=True, **kw)
++            debug=debug, use_async=True, **kw)
+         self.test_file = testfile
+         self.arbiter = arbiter
+         self.arbiters.append(arbiter)
+@@ -265,7 +265,7 @@ class TestCircus(AsyncTestCase):
+ 
+     @classmethod
+     def _create_circus(cls, callable_path, plugins=None, stats=False,
+-                       async=False, arbiter_kw=None, **kw):
++                       use_async=False, arbiter_kw=None, **kw):
+         fd, testfile = mkstemp()
+         os.close(fd)
+         wdir = os.path.dirname(os.path.dirname(os.path.dirname(
+@@ -292,7 +292,7 @@ class TestCircus(AsyncTestCase):
+             arbiter_kw['stats_endpoint'] = "tcp://127.0.0.1:%d" % _gp()
+             arbiter_kw['statsd_close_outputs'] = not debug
+ 
+-        if async:
++        if use_async:
+             arbiter_kw['background'] = False
+             arbiter_kw['loop'] = get_ioloop()
+         else:
+diff --git a/circus/tests/test_client.py b/circus/tests/test_client.py
+index 9a56a11..a0cfca0 100644
+--- a/circus/tests/test_client.py
++++ b/circus/tests/test_client.py
+@@ -90,7 +90,7 @@ class TestWithHook(TestCircus):
+         self.stream = QueueStream()
+         self.errstream = QueueStream()
+         dummy_process = 'circus.tests.support.run_process'
+-        return self._create_circus(dummy_process, async=True,
++        return self._create_circus(dummy_process, use_async=True,
+                                    stdout_stream={'stream': self.stream},
+                                    stderr_stream={'stream': self.errstream},
+                                    hooks=hooks)
+diff --git a/circus/tests/test_watcher.py b/circus/tests/test_watcher.py
+index 5dd857c..4299ed1 100644
+--- a/circus/tests/test_watcher.py
++++ b/circus/tests/test_watcher.py
+@@ -376,7 +376,7 @@ class TestWatcherHooks(TestCircus):
+         return self._create_circus(dummy_process,
+                                    stdout_stream=stdout_stream,
+                                    stderr_stream=stderr_stream,
+-                                   hooks=hooks, debug=True, async=True)
++                                   hooks=hooks, debug=True, use_async=True)
+ 
+     @tornado.gen.coroutine
+     def _stop(self):
+@@ -601,7 +601,7 @@ class RespawnTest(TestCircus):
+     def test_not_respawning(self):
+         oneshot_process = 'circus.tests.test_watcher.oneshot_process'
+         testfile, arbiter = self._create_circus(oneshot_process,
+-                                                respawn=False, async=True)
++                                                respawn=False, use_async=True)
+         yield arbiter.start()
+         watcher = arbiter.watchers[-1]
+         try:
+-- 
+2.14.4
+