Update aosp/master clang for rebase to r230699.

Change-Id: I6a546ab3d4ae37119eebb735e102cca4f80ab520
diff --git a/test/lit.site.cfg.in b/test/lit.site.cfg.in
index 1f0b960..332bcec 100644
--- a/test/lit.site.cfg.in
+++ b/test/lit.site.cfg.in
@@ -18,6 +18,7 @@
 config.clang_staticanalyzer = @ENABLE_CLANG_STATIC_ANALYZER@
 config.clang_examples = @ENABLE_CLANG_EXAMPLES@
 config.enable_shared = @ENABLE_SHARED@
+config.enable_backtrace = "@ENABLE_BACKTRACES@"
 config.host_arch = "@HOST_ARCH@"
 
 # Support substitution of the tools and libs dirs with user parameters. This is