Fix o3tl::make_unique

...after 3f204714 "use std::unique_ptr in
FlatFndBox: and extend o3tl::make_unique to cope with arrays"

Change-Id: I17a07d0be677aa4a5427be4a5c2f05ed8b675726

include/o3tl/make_unique.hxx

@@ -23,7 +23,8 @@ namespace o3tl
  * Can be replaced by std::make_unique when we allow C++14.
  */
 template<typename T, typename... Args>
-typename std::unique_ptr<T> make_unique(Args&& ... args)
+typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
+make_unique(Args&& ... args)
 {
     return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
 }