[PATCH 4/6] Copy in libbacktrace from gcc

[Tom Tromey]

>>>>> "Andrew" == Andrew Burgess <andrew.burgess@embecosm.com> writes:

Andrew> This copies in libbacktrace from the gcc repository as it was in the
Andrew> commit ad3f0ad4bafe377072a53ded468fd9948e659f46.  GDB is going to
Andrew> start using this library soon.

Seems reasonable to me.

Tom