GCC defect fixes.

libraries/chain/controller.cpp

@@ -205,7 +205,7 @@ struct controller_impl {
 
    SET_APP_HANDLER( eosio, eosio, canceldelay );
 
-   fork_db.irreversible.connect( [&]( auto b ) {
+   fork_db.irreversible.connect( [&]( const block_state_ptr& b ) {
                                  on_irreversible(b);
                                  });
 

plugins/net_plugin/net_plugin.cpp

@@ -686,7 +686,7 @@ namespace eosio {
 
       chain_plugin* chain_plug = nullptr;
 
-      constexpr auto stage_str(stages s );
+      constexpr static auto stage_str(stages s);
 
    public:
       explicit sync_manager(uint32_t span);

plugins/state_history_plugin/state_history_plugin.cpp

@@ -315,7 +315,7 @@ struct state_history_plugin_impl : std::enable_shared_from_this<state_history_pl
 
    void do_accept() {
       auto socket = std::make_shared<tcp::socket>(app().get_io_service());
-      acceptor->async_accept(*socket, [self = shared_from_this(), socket, this](auto ec) {
+      acceptor->async_accept(*socket, [self = shared_from_this(), socket, this](const boost::system::error_code& ec) {
          if (stopping)
             return;
          if (ec) {

plugins/wallet_plugin/yubihsm_wallet.cpp

@@ -125,7 +125,7 @@ struct yubihsm_wallet_impl {
 
    void prime_keepalive_timer() {
       keepalive_timer.expires_at(std::chrono::steady_clock::now() + std::chrono::seconds(20));
-      keepalive_timer.async_wait([this](auto ec){
+      keepalive_timer.async_wait([this](const boost::system::error_code& ec){
          if(ec || !session)
             return;
 
@@ -269,4 +269,4 @@ optional<signature_type> yubihsm_wallet::try_sign_digest(const digest_type diges
    return my->try_sign_digest(digest, public_key);
 }
 
-}}
+}}