Fix clang build failures under -Werror:

  - Make hidden overloaded virtual functions explicit, with private 'using base::method'.
  - Change 'virtual' to 'override' in overridden methods.
  - Remove unused private member variables.

Author: Tony Ricciardi

pc/manager.hpp

@@ -55,7 +55,7 @@ namespace pc
   public:
 
     manager();
-    virtual ~manager();
+    ~manager() override;
 
     // solana rpc http connection
     void set_rpc_host( const std::string& );
@@ -151,7 +151,7 @@ namespace pc
     void poll( bool do_wait = true);
 
     // accept new pyth client apps
-    void accept( int fd );
+    void accept( int fd ) override;
 
     // shut-down server
     void teardown();

pc/request.cpp

@@ -76,7 +76,6 @@ void request_sub_set::teardown()
 request::request()
 : svr_( nullptr ),
   clnt_( nullptr ),
-  cb_( nullptr ),
   is_submit_( false ),
   is_recv_( false )
 {

pc/request.hpp

@@ -112,7 +112,6 @@ namespace pc
 
     manager    *svr_;
     rpc_client *clnt_;
-    rpc_sub    *cb_;
     prev_next_t nd_[1];
     node_list_t slist_;
     bool        is_submit_;

pcapps/admin_request.hpp

@@ -25,6 +25,8 @@ namespace pc
     void on_response( rpc::signature_subscribe * ) override;
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_create_sent, e_create_sig,
       e_init_sent, e_init_sig, e_done, e_error
@@ -57,6 +59,8 @@ namespace pc
     void on_response( rpc::signature_subscribe * ) override;
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_create_sent, e_create_sig,
       e_init_sent, e_init_sig, e_done, e_error
@@ -92,6 +96,8 @@ namespace pc
     void submit() override;
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_create_sent, e_create_sig,
       e_add_sent, e_add_sig, e_done, e_error
@@ -100,7 +106,6 @@ namespace pc
     state_t                  st_;
     commitment               cmt_;
     key_pair                 akey_;
-    key_pair                 skey_;
     key_pair                 mkey_;
     rpc::create_account      areq_[1];
     rpc::add_product         sreq_[1];
@@ -127,6 +132,8 @@ namespace pc
     void reset();
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_sent, e_sig, e_done, e_error
     } state_t;
@@ -163,6 +170,8 @@ namespace pc
     void submit() override;
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_create_sent, e_create_sig,
       e_add_sent, e_add_sig, e_done, e_error
@@ -172,7 +181,6 @@ namespace pc
     commitment               cmt_;
     product                 *prod_;
     key_pair                 akey_;
-    key_pair                 skey_;
     key_pair                 mkey_;
     rpc::create_account      areq_[1];
     rpc::add_price           sreq_[1];
@@ -198,6 +206,8 @@ namespace pc
     void submit() override;
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_init_sent, e_init_sig, e_done, e_error
     } state_t;
@@ -229,6 +239,8 @@ namespace pc
     void submit() override;
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_add_sent, e_add_sig, e_done, e_error
     } state_t;
@@ -237,7 +249,6 @@ namespace pc
     commitment               cmt_;
     price                   *px_;
     key_pair                 akey_;
-    key_pair                 mkey_;
     rpc::add_publisher       req_[1];
     rpc::signature_subscribe sig_[1];
   };
@@ -261,6 +272,8 @@ namespace pc
     void submit() override;
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_add_sent, e_add_sig, e_done, e_error
     } state_t;
@@ -292,6 +305,8 @@ namespace pc
     void on_response( rpc::signature_subscribe * ) override;
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_create_sent, e_create_sig,
       e_init_sent, e_init_sig, e_done, e_error
@@ -321,6 +336,8 @@ namespace pc
     void on_response( rpc::account_subscribe * ) override;
 
   private:
+    using request::on_response;
+
     typedef enum {
       e_upd_sent, e_upd_sig, e_get_sent, e_done, e_error
     } state_t;
@@ -348,6 +365,7 @@ namespace pc
     bool get_is_done() const override;
 
   private:
+    using request::on_response;
     typedef enum { e_sent, e_done, e_error } state_t;
     state_t  st_;
     rpc::get_minimum_balance_rent_exemption req_[1];