Explicitly close one more file for Windows.

util/cythonpp.py

@@ -547,7 +547,8 @@ def preprocess_filename(filename, config):
     definitions = {}
     result = []
     including_section = []
-    for line in open(filename):
+    with open(filename) as f:
+        for line in f:
             linecount += 1
             rstripped = line.rstrip()
             stripped = rstripped.lstrip()
@@ -897,7 +898,11 @@ def atomic_write(filename, data):
 
     if os.path.exists(filename):
         os.unlink(filename)
+    try:
         os.rename(tmpname, filename)
+    except:
+        log("Failed to rename '%s' to '%s", tmpname, filename)
+        raise
     dbg('Wrote %s bytes to %s', len(data), filename)