[Bug libstdc++/77801] std::experimental::gcd std::experimental::lcd use non-constexpr std::abs

[ma30002000 at yahoo dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77801

--- Comment #2 from Matthias Schneider <ma30002000 at yahoo dot de> ---
Of course:

[...]
/home/vcs/VideoSDK/vcs-base/include/vcsbase/Time.h:122:203:   in constexpr
expansion of ‘vcsbase::Time::FromInt(ticks, (uncertaintyInTicks / 90u), 0l,
((int64_t)ticksPerMs))’
/home/vcs/VideoSDK/vcs-base/include/vcsbase/TimeImpl.h:88:38:   in constexpr
expansion of ‘std::experimental::fundamentals_v2::gcd<long int, long int>(div,
mul)’
/usr/include/c++/6/experimental/numeric:65:24:   in constexpr expansion of
‘std::experimental::fundamentals_v2::gcd<long int, long int>(__n, (__m % __n))’
/usr/include/c++/6/experimental/numeric:64:23: error: call to non-constexpr
function ‘long int std::abs(long int)’
  : __n == 0 ? std::abs(__m)
               ~~~~~~~~^~~~~
[...]