Fix build on MSVC with PCH off

src/slic3r/Config/Version.cpp

@@ -1,5 +1,7 @@
 #include "Version.hpp"
 
+#include <cctype>
+
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/algorithm/string/trim.hpp>
 #include <boost/nowide/fstream.hpp>

src/slic3r/GUI/GUI_Utils.hpp

@@ -103,7 +103,7 @@ public:
     }
 
     void unbind() { event_storage.reset(nullptr); }
-    explicit operator bool() const noexcept { return !!event_storage; }
+    explicit operator bool() const { return !!event_storage; }
 };
 
 

src/slic3r/GUI/Tab.cpp

@@ -1,4 +1,5 @@
 // #include "libslic3r/GCodeSender.hpp"
+#include "slic3r/Utils/Serial.hpp"
 #include "Tab.hpp"
 #include "PresetBundle.hpp"
 #include "PresetHints.hpp"
@@ -6,7 +7,6 @@
 
 #include "slic3r/Utils/Http.hpp"
 #include "slic3r/Utils/PrintHost.hpp"
-#include "slic3r/Utils/Serial.hpp"
 #include "BonjourDialog.hpp"
 #include "WipeTowerDialog.hpp"
 #include "ButtonsDescription.hpp"