Don't typedef nlink_t in libuv-cffi, it's not defined on Windows. We don't use it anyway.

setup.py

@@ -187,6 +187,7 @@ if not WIN:
     # 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.
+    # Also, we use the type `nlink_t`, which is not defined on Windows.
     cffi_modules.append(
         LIBEV_CFFI_MODULE
     )

src/gevent/libuv/_corecffi_build.py

@@ -33,8 +33,9 @@ _source = read_source('_corecffi_source.c')
 _cdef = _cdef.replace('#define GEVENT_STRUCT_DONE int', '')
 _cdef = _cdef.replace("GEVENT_STRUCT_DONE _;", '...;')
 
+# nlink_t is not used in libuv.
 _cdef = _cdef.replace('#define GEVENT_ST_NLINK_T int',
-                      'typedef int... nlink_t;')
+                      '')
 _cdef = _cdef.replace('GEVENT_ST_NLINK_T', 'nlink_t')