sync: latest libbpf changes from kernel

Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   3820729160440158a014add69cc0d371061a96b2
Checkpoint bpf-next commit: a566e35f1e8b4b3be1e96a804d1cca38b578167c
Baseline bpf commit:        2afd23f78f39da84937006ecd24aa664a4ab052b
Checkpoint bpf commit:      fc11078dd3514c65eabce166b8431a56d8a667cb

Andrii Nakryiko (2):
  libbpf: Fix off-by-one error in ELF sanity check
  libbpf: Don't use kernel-side u32 type in xsk.c

Magnus Karlsson (1):
  libbpf: Fix compatibility for kernels without need_wakeup

 src/libbpf.c |  2 +-
 src/xsk.c    | 83 ++++++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 72 insertions(+), 13 deletions(-)

--
2.17.1

BPF-CHECKPOINT-COMMIT

@@ -1 +1 @@
-2afd23f78f39da84937006ecd24aa664a4ab052b
+fc11078dd3514c65eabce166b8431a56d8a667cb

CHECKPOINT-COMMIT

@@ -1 +1 @@
-3820729160440158a014add69cc0d371061a96b2
+a566e35f1e8b4b3be1e96a804d1cca38b578167c