A bunch of unordered containers tests call library functions, but don't directly include the corresponding header files:
- fabs() (defined in <cmath> which is not included);
- is_permutation() (defined in <algorithm> which is not included);
- next() (defined in <iterator> which is not included).
As a result, these tests won't compile against some conformant libraries.
Please note, that the list of the updated files might be incomplete, since I don't run "post C++11" tests.