About dialog: distinguish between 32 and 64 bit windows build

Change-Id: Id92bb3ed5c19cefed41eeaafe8b956cd2d563bf6
Reviewed-on: https://gerrit.libreoffice.org/13853Reviewed-by: David Ostrovsky <david@ostrovsky.org>
Tested-by: David Ostrovsky <david@ostrovsky.org>

cui/source/dialogs/about.cxx

@@ -252,6 +252,12 @@ OUString AboutDialog::GetVersionString()
 {
     OUString sVersion = m_aVersionTextStr;
 
+#ifdef _WIN64
+
+    sVersion += " (x64)";
+
+#endif
+
     OUString sBuildId = GetBuildId();
 
     OUString pLocaleStr = GetLocaleString();