perf evsel: Introduce perf_evlist

Killing two more perf wide global variables: nr_counters and evsel_list
as a list_head.

There are more operations that will need more fields in perf_evlist,
like the pollfd for polling all the fds in a list of evsel instances.

Use option->value to pass the evsel_list to parse_{events,filters}.

LKML-Reference: <new-submission>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
new file mode 100644
index 0000000..48db91a
--- /dev/null
+++ b/tools/perf/util/evlist.h
@@ -0,0 +1,19 @@
+#ifndef __PERF_EVLIST_H
+#define __PERF_EVLIST_H 1
+
+#include <linux/list.h>
+
+struct perf_evlist {
+	struct list_head entries;
+	int		 nr_entries;
+};
+
+struct perf_evsel;
+
+struct perf_evlist *perf_evlist__new(void);
+void perf_evlist__delete(struct perf_evlist *evlist);
+
+void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry);
+int perf_evlist__add_default(struct perf_evlist *evlist);
+
+#endif /* __PERF_EVLIST_H */