Link to the bug motivating the #defines.
am: 03e7a3eae6

Change-Id: I30e51c738145a131bf945c8e97111a5ae12ec555
diff --git a/Android.bp b/Android.bp
index 4572804..5db4631 100644
--- a/Android.bp
+++ b/Android.bp
@@ -8,6 +8,9 @@
         "linux/lib/xz/xz_dec_stream.c",
     ],
     include_dirs: ["external/xz-embedded/userspace/"],
+
+    // Enable branch/call/jump filters. See http://b/27817327.
     cflags: ["-DXZ_DEC_X86", "-DXZ_DEC_ARM", "-DXZ_DEC_ARMTHUMB"],
+
     export_include_dirs: ["linux/include/linux/"],
 }