Add prebuilts/clang/host/linux-x86 to root.bp.

Bug: http://b/35432050

This is used to support libFuzzer.a prebuilts.

Test: Builds successfully.
Change-Id: I4c2b9e83e88daf136f9017125205b61104c052b8
diff --git a/root.bp b/root.bp
index 219b4e5..f14b047 100644
--- a/root.bp
+++ b/root.bp
@@ -28,6 +28,7 @@
     "libcore",
     "libnativehelper",
     "packages/apps/HTMLViewer",
+    "prebuilts/clang/host/linux-x86",
     "prebuilts/ndk",
     "prebuilts/sdk",
     "system/*",