This requires moving net.link.generic sysctl declaration from if_mib.c
to if.c. Ideally if_mib.c needs just to be merged to if.c, but they
have different license texts.
I'd rather try keep the separation between it and if_mib. (Also, if.c Is huge and worth splitting by itself).
Speaking of static -
One might also consider to simply remove the variable declaration from public space and into the implementation(s) -- possibly along with a comment?
So don't make it static, remove declaration from if_var.h put the declaration into if_mib.c itself? Will work, but it will leave tempting possibility for other modules in kernel to put declaration, too. And I want to make it private to if.c.