Remove libstdc++ dependency from host libbacktrace

The libc++ version of libbacktrace on the host was still linking against
libstdc++, and this was causing problems in art.

(cherry picked from commit a3a8f6d2ab16afaa3018406c694c7d63929f2a83)

Change-Id: Id511dd9cca05c3aa0de2ad13682675ea4ac6424d
1 file changed