Fixed some compiler warnings

sql/semisync_master.cc

@@ -844,7 +844,7 @@ int Repl_semi_sync_master::commit_trx(const char* trx_wait_binlog_name,
     int wait_result;
     PSI_stage_info old_stage;
     THD *thd= current_thd;
-    bool aborted= 0;
+    bool aborted __attribute__((unused)) = 0;
     set_timespec(start_ts, 0);
 
     DEBUG_SYNC(thd, "rpl_semisync_master_commit_trx_before_lock");

sql/semisync_master_ack_receiver.h

@@ -186,7 +186,7 @@ class Ack_listener
       char buff[100];
       /* Clear the signal message */
 #ifndef _WIN32
-      read(local_read_signal, buff, sizeof(buff));
+      (void) !read(local_read_signal, buff, sizeof(buff));
 #else
       recv(local_read_signal, buff, sizeof(buff), 0);
 #endif /* _WIN32 */