Try to fix #685

diff --git a/configure.py b/configure.py
index 64f940b..0cff196 100755 (executable)
--- a/configure.py
+++ b/configure.py
@@ -81,7 +81,7 @@ class Platform(object):
                                  stdout=subprocess.PIPE,
                                  stderr=subprocess.PIPE)
         out, err = popen.communicate()
-        return '/FS ' in str(out)
+        return b'/FS ' in out
 
     def is_windows(self):
         return self.is_mingw() or self.is_msvc()