[Bug c++/116491] GCC defines macro linux if -std is not set, and does not define otherwise

[sergio_nsk at yahoo dot de via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116491

--- Comment #1 from Sergey Markelov <sergio_nsk at yahoo dot de> ---
Expected: GCC should not define the undocumented/non standard macro `linux`.