diff --git a/tox.ini b/tox.ini
index 700ad93..052d760 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,3 +8,6 @@ deps=
 
 commands =
     py.test
+
+setenv =
+    CFLAGS='-stdlib=libc++'
\ No newline at end of file