Use the libcxxabi __cxa_demangle.

Bug: 18930951
Change-Id: If2ea3633ac6dfd4ec975c0f16bdf3dd58e05c614
diff --git a/libc/Android.mk b/libc/Android.mk
index fc4940a..afd586e 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -1221,7 +1221,8 @@
 LOCAL_SYSTEM_SHARED_LIBRARIES :=
 # Only need this for arm since libc++ uses its own unwind code that
 # doesn't mix with the other default unwind code.
-LOCAL_STATIC_LIBRARIES_arm := libunwind_llvm libc++abi
+LOCAL_STATIC_LIBRARIES_arm := libunwind_llvm
+LOCAL_STATIC_LIBRARIES += libc++abi
 LOCAL_ALLOW_UNDEFINED_SYMBOLS := true
 
 # Don't install on release build