Fix etl::chrono floor/ceil/round/abs being declared in the wrong namespace
The duration overloads of floor, ceil, round and abs were defined in
namespace etl rather than etl::chrono, so qualified calls such as
etl::chrono::floor<seconds>(ms) only found the time_point overload and
failed to compile. Moved them into namespace chrono next to
duration_cast and removed the old etl-scope definitions, which also
fixes the unqualified calls made from time_point.h.
Fix comment about rounding behavior
Use cmath functions from std namespace
GCC 16 doesn't support them in the global namespace anymore.
This was disabled explicitly in recent commit
232c948674cff1b4b72c2d6b3acfa7342d096dd1 to prevent using
the <compare> header from STL.
Now, re-enabling by implementing an ETL version of it in compare.h
* Fix compilation with -Wsign-conversion
For tests with GCC and Clang
Fixes https://github.com/ETLCPP/etl/issues/632
* Fix support of negative Id in type_lookup.h: type_from_id
* Fix element access arithmetic in atomic_gcc_sync.h fetch_add/fetch_sub
* Fix rounded_integral_division.h: divide_round_half_odd(): direction is always 1
