[PATCH][_GLIBCXX_DEBUG] Improve valid_range check

[Jonathan Wakely]

On 22/11/19 18:38 +0100, François Dumont wrote:
>Hi
>
>    I noticed that we are not checking that iterators are not singular 
>in valid_range. Moreover __check_singular signature for pointers is 
>not intercepting all kind of pointers in terms of qualification.
>
>    I'd like to commit it next week but considering we are in stage 3 
>I need proper acceptance.
>
>    * include/debug/functions.h: Remove <bits/move.h> include.
>    (__check_singular_aux, __check_singular): Move...
>    * include/debug/helper_functions.h:
>    (__check_singular_aux, __check_singular): ...here.
>    (__valid_range_aux): Adapt to use latter.
>    * testsuite/25_algorithms/copy/debug/2_neg.cc: New.
>
>Tested under Linux x86_64 normal and debug modes.

OK for trunk, thanks.