sync: latest libbpf changes from kernel

Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   b615e5a1e067dcb327482d1af7463268b89b1629
Checkpoint bpf-next commit: e7096c131e5161fa3b8e52a650d7719d2857adfd
Baseline bpf commit:        34e59836565e36fade1464e054a3551c1a0364be
Checkpoint bpf commit:      e42617b825f8073569da76dc4510bfa019b1c35a

Alexei Starovoitov (2):
  libbpf: Fix sym->st_value print on 32-bit arches
  selftests/bpf: Add test for BPF trampoline

Andrii Nakryiko (1):
  libbpf: Fix global variable relocation

Martin KaFai Lau (1):
  bpf: Introduce BPF_TRACE_x helper for the tracing tests

 src/libbpf.c | 45 ++++++++++++++++++++-------------------------
 1 file changed, 20 insertions(+), 25 deletions(-)

--
2.17.1

BPF-CHECKPOINT-COMMIT

@@ -1 +1 @@
-34e59836565e36fade1464e054a3551c1a0364be
+e42617b825f8073569da76dc4510bfa019b1c35a

CHECKPOINT-COMMIT

@@ -1 +1 @@
-b615e5a1e067dcb327482d1af7463268b89b1629
+e7096c131e5161fa3b8e52a650d7719d2857adfd