Fix compile error with -Wunused-function

examples/client.c

@@ -345,6 +345,7 @@ static void setup_nghttp2_callbacks(nghttp2_session_callbacks *callbacks) {
       callbacks, on_data_chunk_recv_callback);
 }
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
 /*
  * Callback function for TLS NPN. Since this program only supports
  * HTTP/2 protocol, if server does not offer HTTP/2 the nghttp2
@@ -365,6 +366,7 @@ static int select_next_proto_cb(SSL *ssl, unsigned char **out,
   }
   return SSL_TLSEXT_ERR_OK;
 }
+#endif /* !OPENSSL_NO_NEXTPROTONEG */
 
 /*
  * Setup SSL/TLS context.

examples/libevent-client.c

@@ -308,6 +308,7 @@ static int on_stream_close_callback(nghttp2_session *session, int32_t stream_id,
   return 0;
 }
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
 /* NPN TLS extension client callback. We check that server advertised
    the HTTP/2 protocol the nghttp2 library supports. If not, exit
    the program. */
@@ -322,6 +323,7 @@ static int select_next_proto_cb(SSL *ssl, unsigned char **out,
   }
   return SSL_TLSEXT_ERR_OK;
 }
+#endif /* !OPENSSL_NO_NEXTPROTONEG */
 
 /* Create SSL_CTX. */
 static SSL_CTX *create_ssl_ctx(void) {

examples/libevent-server.c

@@ -109,6 +109,7 @@ struct app_context {
 static unsigned char next_proto_list[256];
 static size_t next_proto_list_len;
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
 static int next_proto_cb(SSL *ssl, const unsigned char **data,
                          unsigned int *len, void *arg) {
   (void)ssl;
@@ -118,6 +119,7 @@ static int next_proto_cb(SSL *ssl, const unsigned char **data,
   *len = (unsigned int)next_proto_list_len;
   return SSL_TLSEXT_ERR_OK;
 }
+#endif /* !OPENSSL_NO_NEXTPROTONEG */
 
 #if OPENSSL_VERSION_NUMBER >= 0x10002000L
 static int alpn_select_proto_cb(SSL *ssl, const unsigned char **out,

src/HttpServer.cc

@@ -1984,6 +1984,7 @@ HttpServer::HttpServer(const Config *config) : config_(config) {
   };
 }
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
 namespace {
 int next_proto_cb(SSL *s, const unsigned char **data, unsigned int *len,
                   void *arg) {
@@ -1993,6 +1994,7 @@ int next_proto_cb(SSL *s, const unsigned char **data, unsigned int *len,
   return SSL_TLSEXT_ERR_OK;
 }
 } // namespace
+#endif // !OPENSSL_NO_NEXTPROTONEG
 
 namespace {
 int verify_callback(int preverify_ok, X509_STORE_CTX *ctx) {

src/asio_client_tls_context.cc

@@ -35,6 +35,7 @@ namespace nghttp2 {
 namespace asio_http2 {
 namespace client {
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
 namespace {
 int client_select_next_proto_cb(SSL *ssl, unsigned char **out,
                                 unsigned char *outlen, const unsigned char *in,
@@ -46,6 +47,7 @@ int client_select_next_proto_cb(SSL *ssl, unsigned char **out,
   return SSL_TLSEXT_ERR_OK;
 }
 } // namespace
+#endif // !OPENSSL_NO_NEXTPROTONEG
 
 boost::system::error_code
 configure_tls_context(boost::system::error_code &ec,
@@ -54,7 +56,9 @@ configure_tls_context(boost::system::error_code &ec,
 
   auto ctx = tls_ctx.native_handle();
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
   SSL_CTX_set_next_proto_select_cb(ctx, client_select_next_proto_cb, nullptr);
+#endif // !OPENSSL_NO_NEXTPROTONEG
 
 #if OPENSSL_VERSION_NUMBER >= 0x10002000L
   auto proto_list = util::get_default_alpn();

src/asio_server_tls_context.cc

@@ -35,12 +35,14 @@ namespace nghttp2 {
 namespace asio_http2 {
 namespace server {
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
 namespace {
 std::vector<unsigned char> &get_alpn_token() {
   static auto alpn_token = util::get_default_alpn();
   return alpn_token;
 }
 } // namespace
+#endif // !OPENSSL_NO_NEXTPROTONEG
 
 #if OPENSSL_VERSION_NUMBER >= 0x10002000L
 namespace {
@@ -82,6 +84,7 @@ configure_tls_context_easy(boost::system::error_code &ec,
   }
 #endif /* OPENSSL_NO_EC */
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
   SSL_CTX_set_next_protos_advertised_cb(
       ctx,
       [](SSL *s, const unsigned char **data, unsigned int *len, void *arg) {
@@ -93,6 +96,7 @@ configure_tls_context_easy(boost::system::error_code &ec,
         return SSL_TLSEXT_ERR_OK;
       },
       nullptr);
+#endif // !OPENSSL_NO_NEXTPROTONEG
 
 #if OPENSSL_VERSION_NUMBER >= 0x10002000L
   // ALPN selection callback

src/h2load.cc

@@ -1565,6 +1565,7 @@ std::string get_reqline(const char *uri, const http_parser_url &u) {
 }
 } // namespace
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
 namespace {
 int client_select_next_proto_cb(SSL *ssl, unsigned char **out,
                                 unsigned char *outlen, const unsigned char *in,
@@ -1579,6 +1580,7 @@ int client_select_next_proto_cb(SSL *ssl, unsigned char **out,
   return SSL_TLSEXT_ERR_NOACK;
 }
 } // namespace
+#endif // !OPENSSL_NO_NEXTPROTONEG
 
 namespace {
 constexpr char UNIX_PATH_PREFIX[] = "unix:";

src/nghttp.cc

@@ -2222,6 +2222,7 @@ id  responseEnd requestStart  process code size request path)"
 }
 } // namespace
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
 namespace {
 int client_select_next_proto_cb(SSL *ssl, unsigned char **out,
                                 unsigned char *outlen, const unsigned char *in,
@@ -2245,6 +2246,7 @@ int client_select_next_proto_cb(SSL *ssl, unsigned char **out,
   return SSL_TLSEXT_ERR_OK;
 }
 } // namespace
+#endif // !OPENSSL_NO_NEXTPROTONEG
 
 namespace {
 int communicate(

src/shrpx_tls.cc

@@ -80,6 +80,7 @@ const unsigned char *ASN1_STRING_get0_data(ASN1_STRING *x) {
 } // namespace
 #endif // !OPENSSL_1_1_API
 
+#ifndef OPENSSL_NO_NEXTPROTONEG
 namespace {
 int next_proto_cb(SSL *s, const unsigned char **data, unsigned int *len,
                   void *arg) {
@@ -89,6 +90,7 @@ int next_proto_cb(SSL *s, const unsigned char **data, unsigned int *len,
   return SSL_TLSEXT_ERR_OK;
 }
 } // namespace
+#endif // !OPENSSL_NO_NEXTPROTONEG
 
 namespace {
 int verify_callback(int preverify_ok, X509_STORE_CTX *ctx) {