perf_counter: Detect debugfs location

If "/sys/kernel/debug" is not a debugfs mount point, search for the debugfs
filesystem in /proc/mounts, but also allows the user to specify
'--debugfs-dir=blah' or set the environment variable: 'PERF_DEBUGFS_DIR'

Signed-off-by: Jason Baron <jbaron@redhat.com>
[ also made it probe "/debug" by default ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090721181629.GA3094@redhat.com>
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index e3d5529..1ea5d09 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -3,6 +3,8 @@
  * Parse symbolic events/counts passed in as options:
  */
 
+struct option;
+
 extern int			nr_counters;
 
 extern struct perf_counter_attr attrs[MAX_COUNTERS];
@@ -15,3 +17,6 @@
 
 extern void print_events(void);
 
+extern char debugfs_path[];
+extern int valid_debugfs_mount(const char *debugfs);
+