Fix of previous commit, fix of compilation on OSX.

xs/src/slic3r/Utils/Serial.cpp

@@ -1,8 +1,6 @@
 #include "Serial.hpp"
 
 #include <algorithm>
-#include <string>
-#include <vector>
 
 #include <boost/algorithm/string/predicate.hpp>
 

xs/src/slic3r/Utils/Serial.hpp

@@ -3,6 +3,8 @@
 
 #include <memory>
 #include <vector>
+#include <string>
+#include <vector>
 
 namespace Slic3r {
 namespace Utils {