Fix 64-bit conversion errors

src/engine/UpdateInstallDialog.cpp

 #include <sstream>
 #include <string>
 #include <Windows.h>
 
 #include "../shared/Dictionary.h"
 #include "../shared/Utils.h"
 #include "UpdateInstallDialog.h"
 
 namespace
 {
@@ skipping 40 matching lines @@
   }
 
   int GetAverageCharacterWidth(HDC deviceContext)
   {
     std::wstring alphabet;
     for (wchar_t letter = L'A'; letter != 'Z'; letter++)
       alphabet += letter;
     RECT alphabetRect = {};
     DrawTextW(deviceContext, alphabet.c_str(), -1, &alphabetRect,
               DT_CALCRECT | DT_NOPREFIX);
-    return alphabetRect.right / alphabet.length();
+    return alphabetRect.right / static_cast<int>(alphabet.length());
   }
 
   HWND CreateStaticText(HWND parent)
   {
     Dictionary* dictionary = Dictionary::GetInstance();
     std::wstring text = dictionary->Lookup("updater", "install-question-text");
 
     HDC deviceContext = GetDC(parent);
     const int characterWidth = GetAverageCharacterWidth(deviceContext);
     const int lineLength = 40;
@@ skipping 108 matching lines @@
   ShowWindow(window, SW_SHOW);
   MSG message;
   while(GetMessage(&message, 0, 0, 0) > 0)
   {
     TranslateMessage(&message);
     DispatchMessage(&message);
   }
   ShowWindow(window, SW_HIDE);
   return message.wParam == 0;
 }