The __aeabi_memcpy functions are already defined in Android libc.
Redefining them to call memcpy will become recursive when clang/llvm
converts the memcpy call to __aeabi_memcpy.
With this change, we can enable clang/llvm by removing LOCAL_CLANG from Android.mk.

BUG: 12216385
Change-Id: I8b8b4ba7f3ff1e66f8110fc3b6356865a582c1d8