Re: c++20: require gcc12?

[Greg Troxel <gdt%lexort.com@localhost>]

Martin Husemann <martin%duskware.de@localhost> writes:

> This is very strange and probably points at a serious bug in the gcc pkg.
> Any chance to investigate details of the configure failure?
>
> AFAICT there is no c++20 specific test code to compile and the c++
> frontend does understand "-std=c++20".

Really?  That seems bizarre as selecting the std has been the normal
approach for many years and versions.

On gcc10 on NetBSD 10:

  $  c++ --std=c++20
  c++: fatal error: no input files
  compilation terminated.

  $  c++ --std=c++21
  c++: error: unrecognized command-line option ‘--std=c++21’; did you mean ‘--std=c++11’?
  c++: fatal error: no input files
  compilation terminated.

which looks fine (with the caveat that gcc10 will only compile a subset
of c++20 programs, according to gcc docs).