Add new path to visibility rule prior to migration.

BUG: 163786882
Test: TH
Change-Id: I9ee33e64c07384cc8a238a19cf9445085cf7b94f
diff --git a/libunwindstack/Android.bp b/libunwindstack/Android.bp
index 7770b13..8ea286e 100644
--- a/libunwindstack/Android.bp
+++ b/libunwindstack/Android.bp
@@ -171,6 +171,8 @@
         "//system/core/debuggerd",
         "//system/core/init",
         "//system/core/libbacktrace",
+	// Temporary add the new path in preparation for migration.
+        "//system/unwinding/libbacktrace",
     ],
     apex_available: [
         "//apex_available:platform",