Now that we require C++11 and all uses of gdb::unique_ptr and
gdb::move are gone, let's remove their definitions...
With my lazy hat on, I repurposed the header for "generally useful
unique_ptr specializations", and left gdb::unique_xmalloc_ptr in
there. Not sure whether we it'd be better move it out of the gdb
namespace or leave it be. I left it because it's less work and avoids
disrupting yet-unmerged patches that use it.
gdb/ChangeLog:
2016-11-15 Pedro Alves <palves@redhat.com>