perf evsel: Expose the perf_missing_features struct

As tools may need to adjust to missing features, as 'perf top' will, in
the next csets, to cope with a missing 'write_backward' feature.

Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-jelngl9q1ooaizvkcput9tic@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evsel.c

@@ -41,17 +41,7 @@
 
 #include "sane_ctype.h"
 
-static struct {
+struct perf_missing_features perf_missing_features;
-	bool sample_id_all;
-	bool exclude_guest;
-	bool mmap2;
-	bool cloexec;
-	bool clockid;
-	bool clockid_wrong;
-	bool lbr_flags;
-	bool write_backward;
-	bool group_read;
-} perf_missing_features;
 
 static clockid_t clockid;
 

tools/perf/util/evsel.h

@@ -149,6 +149,20 @@ union u64_swap {
 	u32 val32[2];
 };
 
+struct perf_missing_features {
+	bool sample_id_all;
+	bool exclude_guest;
+	bool mmap2;
+	bool cloexec;
+	bool clockid;
+	bool clockid_wrong;
+	bool lbr_flags;
+	bool write_backward;
+	bool group_read;
+};
+
+extern struct perf_missing_features perf_missing_features;
+
 struct cpu_map;
 struct target;
 struct thread_map;