Fix to build without secure renegotiation support
diff --git a/cryptography/hazmat/bindings/openssl/ssl.py b/cryptography/hazmat/bindings/openssl/ssl.py
index 1a2a69e..d4671a5 100644
--- a/cryptography/hazmat/bindings/openssl/ssl.py
+++ b/cryptography/hazmat/bindings/openssl/ssl.py
@@ -364,12 +364,14 @@
"""
CUSTOMIZATIONS = """
-/* Secure renegotiation is supported in OpenSSL >= 0.9.8m */
-#if OPENSSL_VERSION_NUMBER < 0x009080dfL
+/** Secure renegotiation is supported in OpenSSL >= 0.9.8m
+ * But some Linux distributions have back ported some features.
+ */
+#ifndef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
static const long Cryptography_HAS_SECURE_RENEGOTIATION = 0;
-long SSL_get_secure_renegotiation_support(SSL *) = 0;
-static const SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION = 0;
-static const SSL_OP_LEGACY_SERVER_CONNECT = 0;
+long (*SSL_get_secure_renegotiation_support)(SSL *) = NULL;
+const long SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION = 0;
+const long SSL_OP_LEGACY_SERVER_CONNECT = 0;
#else
static const long Cryptography_HAS_SECURE_RENEGOTIATION = 1;
#endif