For #1045, revert macro for TCP keepalive detection, use system macro

trunk/src/app/srs_app_listener.cpp

@@ -228,7 +228,9 @@ srs_error_t SrsTcpListener::listen()
         return srs_error_new(ERROR_SOCKET_CREATE, "create socket. ip=%s, port=%d", ip.c_str(), port);
     }
     
-#ifdef SRS_PERF_SO_KEEPALIVE
+    // Detect alive for TCP connection.
+    // @see https://github.com/ossrs/srs/issues/1044
+#ifdef SO_KEEPALIVE
     int tcp_keepalive = 1;
     if (setsockopt(_fd, SOL_SOCKET, SO_KEEPALIVE, &tcp_keepalive, sizeof(int)) == -1) {
         return srs_error_new(ERROR_SOCKET_SETKEEPALIVE, "setsockopt SO_KEEPALIVE[%d]error. port=%d", tcp_keepalive, port);

trunk/src/core/srs_core_performance.hpp

@@ -190,9 +190,5 @@
 #define SRS_PERF_GLIBC_MEMORY_CHECK
 #undef SRS_PERF_GLIBC_MEMORY_CHECK
 
-// Whether set SO_KEEPALIVE for TCP connection.
-// @see https://github.com/ossrs/srs/issues/1044
-#undef SRS_PERF_SO_KEEPALIVE
-
 #endif