restore this constant, pyopenssl needs it (#3321)

diff --git a/src/_cffi_src/openssl/ssl.py b/src/_cffi_src/openssl/ssl.py
index 12af346..6fdc201 100644
--- a/src/_cffi_src/openssl/ssl.py
+++ b/src/_cffi_src/openssl/ssl.py
@@ -44,6 +44,7 @@
 static const long Cryptography_HAS_SSL_OP_NO_TICKET;
 static const long Cryptography_HAS_NETBSD_D1_METH;
 static const long Cryptography_HAS_ALPN;
+static const long Cryptography_HAS_NEXTPROTONEG;
 static const long Cryptography_HAS_SET_CERT_CB;
 
 static const long SSL_FILETYPE_PEM;
@@ -578,6 +579,8 @@
 static const long Cryptography_HAS_NETBSD_D1_METH = 1;
 #endif
 
+static const long Cryptography_HAS_NEXTPROTONEG = 1;
+
 /* ALPN was added in OpenSSL 1.0.2. */
 #if CRYPTOGRAPHY_OPENSSL_LESS_THAN_102 && !defined(LIBRESSL_VERSION_NUMBER)
 int (*SSL_CTX_set_alpn_protos)(SSL_CTX *,