Only try to configure libev for CFFI if we're building it

appveyor.yml

@@ -122,6 +122,10 @@ install:
   # Note that psutil won't build under PyPy on windows.
   - "%CMD_IN_ENV% pip install -U wheel cython greenlet cffi"
 
+  - ps:
+      if ("${env:PYTHON_ID}" -ne "pypy") {
+         pip install psutil | Out-Null;
+      }
   - ps: "if(Test-Path(\"${env:PYTHON}\\bin\")) {ls ${env:PYTHON}\\bin;}"
   - ps: "if(Test-Path(\"${env:PYTHON}\\Scripts\")) {ls ${env:PYTHON}\\Scripts;}"
 

setup.py

@@ -59,6 +59,7 @@ EXT_MODULES = [
     LOCAL,
 ]
 
+LIBEV_CFFI_MODULE = 'src/gevent/libev/_corecffi_build.py:ffi'
 cffi_modules = []
 
 if not WIN:
@@ -69,7 +70,7 @@ if not WIN:
     # 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'
+        LIBEV_CFFI_MODULE
     )
 
 if not WIN:
@@ -137,7 +138,8 @@ def run_setup(ext_modules, run_make):
             # to build the CFFI module. We need to configure libev
             # because the CORE Extension won't.
             # TODO: Generalize this.
-            system(libev_configure_command)
+            if LIBEV_CFFI_MODULE in cffi_modules and not WIN:
+                system(libev_configure_command)
 
         MakeSdist.make()