[Bug libstdc++/100017] [11/12 regression] error: 'fenv_t' has not been declared in '::' -- canadian compilation fails

["aladjev.andrew at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100017

--- Comment #32 from Andrew Aladjev <aladjev.andrew at gmail dot com> ---
I've added include_next_fenv dirty patch. I want just to quickly explain how to
use it.

First of all I've noticed (many years ago) that gcc developers are making
releases based on limited set of basic tests. These tests include one self
compilation using same version of gcc: gcc 11.2.0 amd64 -> gcc 11.2.0 amd64.
But in reality you have the following case:

gcc #{prev_version} #{platform1} #{env1} -> gcc #{next_version} #{platform2}
#{env2}

This movement is very hard task in practice, so I've added an additional step:

gcc #{prev_version} #{platform1} #{env1} -> dirty gcc #{next_version}
#{platform2} #{dirty_env2} -> gcc #{next_version} #{platform2} #{env2}

"dirty gcc" and "dirty env" step is very usefull when nobody have a solution.
You can invent your own dirty bicycle, apply it and you will receive clean gcc
on target platform in the last step anyway.

You may also review the following repo
https://github.com/andrew-aladev/test-images with my some test images.

Thank you.