perf bpf: Add license(NAME) helper

To further reduce boilerplate.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-vst6hj335s0ebxzqltes3nsc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/include/bpf/bpf.h

@@ -2,4 +2,9 @@
 #ifndef _PERF_BPF_H
 #define _PERF_BPF_H
 #define SEC(NAME) __attribute__((section(NAME),  used))
+
+#define license(name) \
+char _license[] SEC("license") = #name; \
+int _version SEC("version") = LINUX_VERSION_CODE;
+
 #endif /* _PERF_BPF_H */