Build against greenlet 0.4.17

Fixes #1674

CHANGES.rst

@@ -6,6 +6,42 @@
 
 .. towncrier release notes start
 
+20.6.3.dev0 (2020-09-22)
+========================
+
+
+Features
+--------
+
+- The embedded libev is now asked to detect the availability of
+  ``clock_gettime`` and use the realtime and/or monotonic clocks, if
+  they are available.
+
+  On Linux, this can reduce the number of system calls libev makes.
+  Originally provided by Josh Snyder.
+  See :issue:`issue1648`.
+
+
+Bugfixes
+--------
+
+- The ``DummyThread`` objects created automatically by certain
+  operations when the standard library threading module is
+  monkey-patched now match the naming convention the standard library
+  uses ("Dummy-12345"). Previously (since gevent 1.2a2) they used
+  "DummyThread-12345".
+  See :issue:`1659`.
+- Fix compatibility with dnspython 2.
+
+  .. caution:: This currently means that it can be imported. But it
+               cannot yet be used. gevent has a pinned dependency on
+               dnspython < 2 for now.
+  See :issue:`1661`.
+
+
+----
+
+
 20.6.2 (2020-06-16)
 ===================
 

deps/greenlet/greenlet.h

@@ -11,12 +11,20 @@
 extern "C" {
 #endif
 
-#define GREENLET_VERSION "0.4.16"
+#define GREENLET_VERSION "0.4.17"
 
 #if PY_VERSION_HEX >= 0x030700A3
 #  define GREENLET_USE_EXC_INFO
 #endif
 
+#ifndef GREENLET_USE_CONTEXT_VARS
+#ifdef Py_CONTEXT_H
+#define GREENLET_USE_CONTEXT_VARS 1
+#else
+#define GREENLET_USE_CONTEXT_VARS 0
+#endif
+#endif
+
 typedef struct _greenlet {
 	PyObject_HEAD
 	char* stack_start;
@@ -38,6 +46,9 @@ typedef struct _greenlet {
 	PyObject* exc_traceback;
 #endif
 	PyObject* dict;
+#if GREENLET_USE_CONTEXT_VARS
+	PyObject* context;
+#endif
 } PyGreenlet;
 
 #define PyGreenlet_Check(op)      PyObject_TypeCheck(op, &PyGreenlet_Type)

docs/changes/issue1674.bugfix

@@ -0,0 +1,4 @@
+On CPython, depend on greenlet >= 0.4.17. This version is binary
+incompatible with earlier releases on CPython 3.7 and later. Note that
+gevent does not rely on its new support for context variables since
+gevent provides the same API to older versions of Python.

pyproject.toml

@@ -24,8 +24,9 @@ requires = [
      # See version requirements in setup.py
      "cffi >= 1.12.3 ; platform_python_implementation == 'CPython'",
      # Python 3.7 requires at least 0.4.14, which is ABI incompatible with earlier
-     # releases. Python 3.9 and 3.10 require 0.4.16
-     "greenlet >= 0.4.16 ; platform_python_implementation == 'CPython'",
+     # releases. Python 3.9 and 3.10 require 0.4.16;
+     # 0.4.17 is ABI incompatible with earlier releases.
+     "greenlet >= 0.4.17 ; platform_python_implementation == 'CPython'",
 ]
 
 [tool.towncrier]

setup.py

@@ -193,7 +193,7 @@
     # since we compile cython code that extends the greenlet object.
     # Binary compatibility would break if the greenlet struct changes.
     # (Which it did in 0.4.14 for Python 3.7)
-    'greenlet >= 0.4.16; platform_python_implementation=="CPython"',
+    'greenlet >= 0.4.17; platform_python_implementation=="CPython"',
 ]
 
 # Note that we don't add cffi to install_requires, it's