Stop lying to libev about compiling with llvm on darwin (macOS).

The problems with memory fences that were referenced in 7f4e0b01 should be long gone: XCode has moved on, as has libev, and the conditionals in libev also check for __clang__ too, so it wasn't doing anything anymore.

Also update pyproject.toml to reflect what we're actually using version-wise, and add a note about why we use the build backend we do.

.travis.yml

@@ -140,7 +140,7 @@ jobs:
         # output (pip install uses a random temporary directory, making this difficult)
         - python setup.py bdist_wheel
         - pip uninstall -y gevent
-        - pip install `ls dist/*whl`[test]
+        - pip install --no-compile `ls dist/*whl`[test]
       script: ccache -s
       before_script: true
       after_success: true

CHANGES.rst

@@ -7,7 +7,7 @@
 1.5a2 (unreleased)
 ==================
 
-- Nothing changed yet.
+- Update to Cython 0.29.7 and cffi 1.12.3.
 
 1.5a1 (2019-05-02)
 ==================

_setuplibev.py

@@ -21,7 +21,6 @@ from _setuputils import make_universal_header
 from _setuputils import LIBRARIES
 from _setuputils import DEFINE_MACROS
 from _setuputils import glob_many
-from _setuputils import dep_abspath
 from _setuputils import should_embed
 
 
@@ -90,8 +89,6 @@ def build_extension():
                                ('EV_EMBED_ENABLE', '0'),
                                ("EV_PERIODIC_ENABLE", '0')]
         CORE.configure = configure_libev
-        if sys.platform == "darwin":
-            os.environ["CPPFLAGS"] = ("%s %s" % (os.environ.get("CPPFLAGS", ""), "-U__llvm__")).lstrip()
         if os.environ.get('GEVENTSETUP_EV_VERIFY') is not None:
             CORE.define_macros.append(('EV_VERIFY', os.environ['GEVENTSETUP_EV_VERIFY']))
     else:

_setuputils.py

@@ -160,9 +160,6 @@ def _system(cmd, cwd=None, env=None, **kwargs):
     if 'shell' not in kwargs:
         kwargs['shell'] = True
     env = env or os.environ.copy()
-    if env.get('CC', '').startswith('ccache '):
-        # Running configure scripts under ccache just adds overhead.
-        env['CC'] = env['CC'][7:]
     return check_call(cmd, cwd=cwd, env=env, **kwargs)
 
 

pyproject.toml

 [build-system]
+# Our setup.py imports other things from this directory, meaning
+# in needs to be on sys.path. That's not guaranteed in a PEP517 world;
+# the __legacy__ build module makes that true. Ultimately we need to do that
+# ourself (and/or continue to simplify our build system).
 build-backend = "setuptools.build_meta:__legacy__"
 requires = [
      "setuptools >= 40.8.0",
@@ -9,9 +13,9 @@ requires = [
      # name to be created so that we can have both foo.py and _foo.so
      # at the same time. 0.29 fixes some issues with Python 3.7,
      # and adds the 3str mode for transition to Python 3.
-     "Cython >= 0.29.6",
+     "Cython >= 0.29.7",
      # See version requirements in setup.py
-     "cffi >= 1.12.2 ; platform_python_implementation == 'CPython'",
+     "cffi >= 1.12.3 ; platform_python_implementation == 'CPython'",
      # Python 3.7 requires at least 0.4.14, which is ABI incompatible with earlier
      "greenlet>=0.4.14 ; platform_python_implementation == 'CPython'",
 ]