[Bug target/91135] [9/10 Regression] __linux__ not defined with -mcall-aixdesc on 9.x and ppc64

[gcc at octaforge dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91135

--- Comment #5 from Daniel Kolesa <gcc at octaforge dot org> ---
I don't know 100% *what* the kernel uses it for, I just know it does. If I
remove it, linking vmlinux fails (with thousands of undefined references) so it
seems to require that specific ABI for whatever reason; my best guess is that
it requires the symbol names to be emitted with a dot, and it won't without
that flag, but I might as well be wrong.