Include missing headers and simplify thread func signature

include/modbuspp/data.h

@@ -22,6 +22,7 @@
 #include <type_traits>
 #include <limits>
 #include <string>
+#include <stdexcept>
 
 #include <modbuspp/global.h>
 #include <modbuspp/swap.h>

src/server.cpp

@@ -423,7 +423,7 @@ namespace Modbus {
 
   // ---------------------------------------------------------------------------
   // static
-  void * Server::Private::loop (std::future<void> run, Private * d) {
+  void Server::Private::loop (std::future<void> run, Private * d) {
     int rc;
 
     while (run.wait_for (std::chrono::milliseconds (100)) == std::future_status::timeout) {

src/server_p.h

@@ -39,7 +39,7 @@ namespace Modbus {
 
       BufferedSlave * addSlave (int slaveAddr, Device * master);
 
-      static void * loop (std::future<void> run, Private * d);
+      static void loop (std::future<void> run, Private * d);
       static int receive (Private * d);
 
       int sock;