From: Rusty Russell <rusty@rustcorp.com.au>

# lsmod
Module                  Size  Used by
1                      26060  6
#

The compiler #define's unix to 1: we use -DKBUILD_MODNAME=unix.  We used to
#undef unix at the top of af_unix.c, but now the name is inserted by
modpost, that doesn't help.

#undef unix in modpost.c's generated C file.