PATCH: Add x86-64 x86_64/bits/statvfs.h

[Roland McGrath]

> __KERNEL_WORDSIZE may be confusing since you can run
> ia32 binaries under x86-64 kernel.  

Ok, then make it __SYSCALL_WORDSIZE to match __syscall_slong_t.

> Here is a patch to add __WORDSIZE_NO_STATVFSBUF_F_UNUSED.

I prefer something that is more general.