[!758] fix C++20 and GCC 10 issues (!840) · Merge requests · Core Modules / dune-common

Merge branch 'gcc10' into 'master'

See merge request [!758 (merged)]

(cherry picked from commit a9fbe94d)

b65b1e2c [C++20] use std::allocator_traits 98e4122a [GCC 10] do not test SIMD with wide character types

[!758] fix C++20 and GCC 10 issues