[3.7] bpo-32257: Add ssl.OP_NO_RENEGOTIATION (GH-5904) (#6877)

The ssl module now contains OP_NO_RENEGOTIATION constant, available with
OpenSSL 1.1.0h or 1.1.1.

Note, OpenSSL 1.1.0h hasn't been released yet.

Signed-off-by: Christian Heimes <christian@python.org>
(cherry picked from commit 67c48016638aac9a15afe6fd6754d53d2bdd6b76)

Co-authored-by: Christian Heimes <christian@python.org>
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index 7670833..bf379f0 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -5845,6 +5845,10 @@
     PyModule_AddIntConstant(m, "OP_ENABLE_MIDDLEBOX_COMPAT",
                             SSL_OP_ENABLE_MIDDLEBOX_COMPAT);
 #endif
+#ifdef SSL_OP_NO_RENEGOTIATION
+    PyModule_AddIntConstant(m, "OP_NO_RENEGOTIATION",
+                            SSL_OP_NO_RENEGOTIATION);
+#endif
 
 #ifdef X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT
     PyModule_AddIntConstant(m, "HOSTFLAG_ALWAYS_CHECK_SUBJECT",