Macro starnix_syscalls::for_each_arch_syscall

macro_rules! for_each_arch_syscall {
    {$callback:ident; $($context:ident;)* ; $($common_name:ident,)*} => { ... };
}

Helper for for_each_syscall! that adds any architecture-specific syscalls.

X86_64 has many unique syscalls for legacy reasons. Newer architectures funnel some of these through some newer and more general variants. The variants used by other platforms are listed in the comments below.