Backport of patch to gdb 8.0 branch.

[Joel Brobecker]

> I'm looking for a backport of
> https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=957f6b39cab6cac0e4c54e650c7f75109544ac1d
> to the gdb-8.0-branch. The patch allows building with full debug trace
> enabled on AArch64.
> 
> Ok for gdb-8.0-branch?

If not already done so, please create a PR in bugzilla that explains
the problem this patch is fixing. Once this is done, can you add that
PR number to the ChangeLog and revision log of the commit you'd like
to backport?

Here is an example that shows a PR with associated commits:
https://sourceware.org/bugzilla/show_bug.cgi?id=22849

This is to follow part of our procedures aiming at properly documenting
all changes that go into a release branch after we make the first
release on that branch.

-- 
Joel