Try to compile libuv as CFFI on PyPy/Windows.

appveyor.yml

@@ -10,12 +10,11 @@ environment:
     # Pre-installed Python versions, which Appveyor may upgrade to
     # a later point release.
 
-    # XXX: Sadly, PyPy won't link CFFI on Win32
-    # - PYTHON: "C:\\pypy-4.0.1-win32"
-    #   PYTHON_ID: "pypy"
-    #   PYTHON_EXE: pypy
-    #   PYTHON_VERSION: "2.7.x"
-    #   PYTHON_ARCH: "32"
+    - PYTHON: "C:\\pypy2-v5.9.0-win32"
+      PYTHON_ID: "pypy"
+      PYTHON_EXE: pypy
+      PYTHON_VERSION: "2.7.x"
+      PYTHON_ARCH: "32"
 
     - PYTHON: "C:\\Python36-x64"
       PYTHON_VERSION: "3.6.x" # currently 3.6.0
@@ -91,14 +90,11 @@ install:
         New-Item -ItemType directory -Path "$env:PYTMP" | Out-Null;
       }
       if ("${env:PYTHON_ID}" -eq "pypy") {
-        if (!(Test-Path "${env:PYTMP}\pypy-4.0.1-win32.zip")) {
-          (New-Object Net.WebClient).DownloadFile('https://bitbucket.org/pypy/pypy/downloads/pypy-4.0.1-win32.zip', "${env:PYTMP}\pypy-4.0.1-win32.zip");
-        }
-        7z x -y "${env:PYTMP}\pypy-4.0.1-win32.zip" -oC:\ | Out-Null;
-        if (!(Test-Path "${env:PYTMP}\get-pip.py")) {
-          (New-Object Net.WebClient).DownloadFile('https://bootstrap.pypa.io/get-pip.py', "${env:PYTMP}\get-pip.py");
+        if (!(Test-Path "${env:PYTMP}\pypy2-v5.9.0-win32.zip")) {
+          (New-Object Net.WebClient).DownloadFile('https://bitbucket.org/pypy/pypy/downloads/pypy2-5.9.0-win32.zip', "${env:PYTMP}\pypy2-v5.9.0-win32.zip");
         }
-        & "${env:PYTHON}\pypy.exe" "${env:PYTMP}\get-pip.py";
+        7z x -y "${env:PYTMP}\pypy2-v5.9.0-win32.zip" -oC:\ | Out-Null;
+        & "${env:PYTHON}\pypy.exe" "-mensurepip";
 
       }
       elseif (-not(Test-Path($env:PYTHON))) {
@@ -123,8 +119,7 @@ install:
   # compiled extensions and are not provided as pre-built wheel packages,
   # pip will build them from source using the MSVC compiler matching the
   # target Python version and architecture
-  # NOTE: psutil won't install under PyPy.
-  - "%CMD_IN_ENV% pip install -U wheel cython greenlet psutil"
+  - "%CMD_IN_ENV% pip install -U wheel cython greenlet psutil cffi"
 
   - ps: "if(Test-Path(\"${env:PYTHON}\\bin\")) {ls ${env:PYTHON}\\bin;}"
   - ps: "if(Test-Path(\"${env:PYTHON}\\Scripts\")) {ls ${env:PYTHON}\\Scripts;}"

setup.py

@@ -7,7 +7,7 @@ import os
 from _setuputils import read
 from _setuputils import read_version
 from _setuputils import system
-from _setuputils import PYPY, WIN, CFFI_WIN_BUILD_ANYWAY
+from _setuputils import PYPY, WIN
 from _setuputils import IGNORE_CFFI
 from _setuputils import ConfiguringBuildExt
 from _setuputils import MakeSdist
@@ -19,15 +19,6 @@ from _setuputils import BuildFailed
 from setuptools import Extension, setup
 from setuptools import find_packages
 
-if PYPY and WIN and not CFFI_WIN_BUILD_ANYWAY:
-    # We can't properly handle (hah!) file-descriptors and
-    # handle mapping on Windows/CFFI, because the file needed,
-    # libev_vfd.h, can't be included, linked, and used: it uses
-    # Python API functions, and you're not supposed to do that from
-    # CFFI code. Plus I could never get the libraries= line to ffi.compile()
-    # correct to make linking work.
-    raise Exception("Unable to install on PyPy/Windows")
-
 if WIN:
     # Make sure the env vars that make.cmd needs are set
     if not os.environ.get('PYTHON_EXE'):
@@ -68,12 +59,23 @@ EXT_MODULES = [
     LOCAL,
 ]
 
-cffi_modules = [
-    'src/gevent/libev/_corecffi_build.py:ffi',
-]
+cffi_modules = []
+
+if not WIN:
+    # We can't properly handle (hah!) file-descriptors and
+    # handle mapping on Windows/CFFI with libev, because the file needed,
+    # libev_vfd.h, can't be included, linked, and used: it uses
+    # Python API functions, and you're not supposed to do that from
+    # CFFI code. Plus I could never get the libraries= line to ffi.compile()
+    # correct to make linking work.
+    cffi_modules.append(
+        'src/gevent/libev/_corecffi_build.py:ffi'
+    )
 
 if not WIN:
     EXT_MODULES.append(LIBUV)
+
+if not WIN or PYPY:
     cffi_modules.append('src/gevent/libuv/_corecffi_build.py:ffi')
 
 if PYPY: