Provide compatibility shim for std::make_unique().

make_unique is C++14 only.  This provides a shim for C++11-only compilers.

Change-Id: Ibaa79822a7a6cfa8020c201c2edea1754650f570

wpilibc/wpilibC++/include/Base.h

@@ -68,3 +68,41 @@ struct HasBeenMoved {
   std::atomic<bool> moved{false};
   operator bool() const { return moved; }
 };
+
+// Define make_unique for C++11-only compilers
+#if __cplusplus == 201103L
+#include <cstddef>
+#include <memory>
+#include <type_traits>
+#include <utility>
+namespace std {
+template <class T>
+struct _Unique_if {
+  typedef unique_ptr<T> _Single_object;
+};
+
+template <class T>
+struct _Unique_if<T[]> {
+  typedef unique_ptr<T[]> _Unknown_bound;
+};
+
+template <class T, size_t N>
+struct _Unique_if<T[N]> {
+  typedef void _Known_bound;
+};
+
+template <class T, class... Args>
+typename _Unique_if<T>::_Single_object make_unique(Args &&... args) {
+  return unique_ptr<T>(new T(std::forward<Args>(args)...));
+}
+
+template <class T>
+typename _Unique_if<T>::_Unknown_bound make_unique(size_t n) {
+  typedef typename remove_extent<T>::type U;
+  return unique_ptr<T>(new U[n]());
+}
+
+template <class T, class... Args>
+typename _Unique_if<T>::_Known_bound make_unique(Args &&...) = delete;
+}  // namespace std
+#endif