[bionic] LP#1758856 -- retpoline hinting support

[Seth Forshee]

On Mon, Mar 26, 2018 at 04:07:45PM +0100, Andy Whitcroft wrote:
> We have been having horrible problems with the retpoline information as
> recorded in the ABI changing on every update.  The below pull-request
> brings in some new support utilising the upstream retpoline annotations.
> As well as bringing in some new annotations where needed.
> 
> This should in time bring us to the situation where the retpoline
> information for every branch is empty.  Where unannotated entries remain
> they are in review and will be coverered off in later updates.  These
> are not regressions.
> 
> Proposing for bionic.

I tested this with bionic, for non-amd64 arches I'm getting an error
packaging the headers:

# We do not need the retpoline information.
find /tmp/kernel-sforshee-dc36af1-llEk/build/debian/linux-headers-4.15.0-14-generic/usr/src/linux-headers-4.15.0-14-generic -name \*.o.ur-\* | xargs rm
rm: missing operand

Surprisingly I got that for i386 too, which I would have expected to
have some of these files.