diff --git a/bin/cythonize.py b/bin/cythonize.py
index 81e0248d6..04e51ba2c 100755
--- a/bin/cythonize.py
+++ b/bin/cythonize.py
@@ -55,7 +55,8 @@ def process_pyx(fromfile, tofile):
 
     try:
         try:
-            r = subprocess.call(['cython'] + flags + ['-o', tofile, fromfile])
+            r = subprocess.call(['cython'] + flags + ['-o', tofile, fromfile],
+                                shell=True, env=os.environ) # See Issue #791
             if r != 0:
                 raise Exception('Cython failed')
         except OSError: