perf script: Add a setting for maximum stack depth

Add a setting for maximum stack depth in preparation for allowing for
synthesized callchains.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-19-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 15c84ca..84a02eae 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1800,7 +1800,7 @@
 
 		if (thread__resolve_callchain(al->thread, evsel,
 					      sample, NULL, NULL,
-					      PERF_MAX_STACK_DEPTH) != 0) {
+					      stack_depth) != 0) {
 			if (verbose)
 				error("Failed to resolve callchain. Skipping\n");
 			return;