perf tools: Add --buildid-dir option to set cache directory

Adding --buildid-dir to be able to set specific cache directory. It's
going to be handy for buildid tests coming in shortly.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1417460789-13874-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 419bee0..abc445e 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -153,7 +153,7 @@
 extern void set_die_routine(void (*routine)(const char *err, va_list params) NORETURN);
 
 extern int prefixcmp(const char *str, const char *prefix);
-extern void set_buildid_dir(void);
+extern void set_buildid_dir(const char *dir);
 
 static inline const char *skip_prefix(const char *str, const char *prefix)
 {