Prepare for self select.

src/core/config/Config_platform.h

@@ -56,6 +56,7 @@ static const option options[] = {
     { "http-no-restricted",    0, nullptr, IConfig::HttpRestrictedKey     },
     { "daemon",                0, nullptr, IConfig::DaemonKey             },
     { "daemon-poll-interval",  1, nullptr, IConfig::DaemonPollKey         },
+    { "self-select",           1, nullptr, IConfig::SelfSelectKey         },
 #   endif
     { "av",                    1, nullptr, IConfig::AVKey                 },
     { "background",            0, nullptr, IConfig::BackgroundKey         },

src/core/config/usage.h

@@ -62,6 +62,7 @@ static inline const std::string &usage()
 #   ifdef XMRIG_FEATURE_HTTP
     u += "      --daemon                  use daemon RPC instead of pool for solo mining\n";
     u += "      --daemon-poll-interval=N  daemon poll interval in milliseconds (default: 1000)\n";
+    u += "      --self-select=URL         self-select block templates from URL\n";
 #   endif
 
     u += "  -r, --retries=N               number of times to retry before switch to backup server (default: 5)\n";