perf annotate: Factor out get/free_srcline()

Currently external addr2line tool is used for srcline sort key and
annotate with srcline info.  Separate the common code to prepare
upcoming enhancements.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1378876173-13363-5-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/util.h

@@ -297,4 +297,9 @@ struct parse_tag {
 };
 
 unsigned long parse_tag_value(const char *str, struct parse_tag *tags);
+
+#define SRCLINE_UNKNOWN  ((char *) "??:0")
+
+char *get_srcline(const char *dso_name, unsigned long addr);
+void free_srcline(char *srcline);
 #endif /* GIT_COMPAT_UTIL_H */