[Bug c++/78920] libstdc++ defines a macro named "major"

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78920

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This comes from glibc headers. G++ defines _GNU_SOURCE which is why this
happens.  There is a duplicate already.