More n3644 changes - forward_list and deque

[Sebastian Redl]

On 06.08.2013, at 17:40, Howard Hinnant wrote:

> This behavior mimics the defined/undefined behavior for pointers described in [expr.eq] and [expr.rel].  j1 and j2 point to the same object, so they are both equality comparable and less-than comparable.  i1, i2 both point to different objects (none at all), and not to the same object as j1 and j2.  [expr.eq] says that all pointers are equality comparable, and this is reflected in the above test.  However [expr.rel] defines operator<() only for pointers pointing into the same object.

But comparison between pointers into different objects is unspecified, not undefined. I don't think trapping is a valid outcome.

Sebastian