Switch to clang-3859424.

Bug: http://b/36442361
Test: Build and run multiple devices/targets.

(cherry picked from commit 073ab0a70725f4af129ff08be0e20fb6693370f3)

Change-Id: Ia057cfac4cb8185d6c6057390a9790a4657156a9
diff --git a/core/clang/versions.mk b/core/clang/versions.mk
index abed69b..c5cc690 100644
--- a/core/clang/versions.mk
+++ b/core/clang/versions.mk
@@ -1,4 +1,4 @@
 ## Clang/LLVM release versions.
 
-LLVM_PREBUILTS_VERSION ?= clang-3688880
+LLVM_PREBUILTS_VERSION ?= clang-3859424
 LLVM_PREBUILTS_BASE ?= prebuilts/clang/host