linux-next: build failure after merge of the bpf-next tree

Hi all,

After merging the bpf-next tree, today's linux-next build (perf) failed
like this:

make[3]: *** No rule to make target 'libbpf_util.h', needed by '/home/sfr/next/perf/staticobjs/xsk.o'.  Stop.

Caused by commit

  7e8bbe24cb8b ("libbpf: xsk: Move barriers from libbpf_util.h to xsk.h")

I have used the bpf tree from next-20210310 for today.

-- 
Cheers,
Stephen Rothwell