perf bpf: Ignore deprecation warning when using libbpf's btf__get_from_id()

Perf code re-implements libbpf's btf__load_from_kernel_by_id() API as
a weak function, presumably to dynamically link against old version of
libbpf shared library. Unfortunately this causes compilation warning
when perf is compiled against libbpf v0.6+.

For now, just ignore deprecation warning, but there might be a better
solution, depending on perf's needs.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: kernel-team@fb.com
LPU-Reference: 20210914170004.4185659-1-andrii@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: anakryiko

tools/perf/util/bpf-event.c

@@ -24,7 +24,10 @@
 struct btf * __weak btf__load_from_kernel_by_id(__u32 id)
 {
        struct btf *btf;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
        int err = btf__get_from_id(id, &btf);
+#pragma GCC diagnostic pop
 
        return err ? ERR_PTR(err) : btf;
 }