Use correct, not American spelling.
diff --git a/ssl/ssltest.c b/ssl/ssltest.c
index 2d6c849..efdfd48 100644
--- a/ssl/ssltest.c
+++ b/ssl/ssltest.c
@@ -503,7 +503,7 @@
* Useful functions for querying the state of BIO pair endpoints:
*
* BIO_ctrl_pending(bio) number of bytes we can read now
- * BIO_ctrl_get_read_request(bio) number of bytes needed to fulfill
+ * BIO_ctrl_get_read_request(bio) number of bytes needed to fulfil
* other side's read attempt
* BIO_ctrl_get_write_guarantee(bio) number of bytes we can write now
*