Fixed compiler errors in the examples

STL_Extension/examples/STL_Extension/Dispatch_output_iterator.cpp

@@ -21,6 +21,7 @@ int main()
     std::back_inserter(b),
     std::back_inserter(c));
 
+  typedef boost::variant<int, double, char> var;
   var va = 23; var vb = 4.2; var vc = 'x';
 
   // goes to a

STL_Extension/examples/STL_Extension/Overload.cpp

@@ -1,9 +1,11 @@
 #include <iostream>
 #include <CGAL/Overload.h>
+#include <CGAL/compiler_config.h>
 
 // This file requires a compiler with support for the C++0x features auto and lambda
 int main()
 {
+#if !defined(CGAL_CFG_NO_CPP0X_VARIADIC_TEMPLATES) && !defined(CGAL_CFG_NO_CPP0X_TUPLE) && !defined(CGAL_CFG_NO_CPP0X_RVALUE_REFERENCE)
   auto overload = make_overload(
     function<int(int)>([](int) {  return 1; }),
     function<int(char)>([](char) {  return 2; }), 
@@ -11,7 +13,7 @@ int main()
     );
 
   std::cout << o(1) << o('a') << " " << o(2.0) << std::endl;
-
+#endif
   return 0;
 }