sync: latest libbpf changes from kernel

Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   92a871ab9fa59a74d013bc04f321026a057618e7
Checkpoint bpf-next commit: 2ab256e93249f5ac1da665861aa0f03fb4208d9c
Baseline bpf commit:        577e4432f3ac810049cb7e6b71f4d96ec7c6e894
Checkpoint bpf commit:      dced881ead78e4d6add3735d02a9186ba2415630

Arnaldo Carvalho de Melo (1):
  tools headers UAPI: Sync linux/fcntl.h with the kernel sources

Cupertino Miranda (1):
  libbpf: Add support to GCC in CORE macro definitions

Martin Kelly (1):
  bpf: Clarify batch lookup/lookup_and_delete semantics

Matt Bobrowski (1):
  libbpf: Make remark about zero-initializing bpf_*_info structs

 include/uapi/linux/bpf.h   |  6 ++++-
 include/uapi/linux/fcntl.h |  3 +++
 src/bpf.h                  | 39 ++++++++++++++++++++++++---------
 src/bpf_core_read.h        | 45 ++++++++++++++++++++++++++++++++------
 4 files changed, 75 insertions(+), 18 deletions(-)

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>

BPF-CHECKPOINT-COMMIT

@@ -1 +1 @@
-577e4432f3ac810049cb7e6b71f4d96ec7c6e894
+dced881ead78e4d6add3735d02a9186ba2415630

CHECKPOINT-COMMIT

@@ -1 +1 @@
-92a871ab9fa59a74d013bc04f321026a057618e7
+2ab256e93249f5ac1da665861aa0f03fb4208d9c