Use of LTO

[raof at ubuntu.com]

On Fri, May 20, 2016 at 9:31 PM, Alan Griffiths 
<alan.griffiths at canonical.com> wrote:
> Recently I encountered a problem (lp:1583536) with shipping an archive
> with objects compiled with -flto in our mirtest-dev package.
> 
> My fix was:
> https://code.launchpad.net/~alan-griffiths/mir/fix-1583536/+merge/295227
> and just suppressed -flto for that archive.
> 
> But I've been thinking: should we use LTO for anything other than the
> shared objects we ship? It takes an age for the unit tests (for 
> example)
> to link with LTO, and while the binaries are smaller is that really 
> the
> right trade off?
> 
> Moving the -flto options to the src tree rather than root might be the
> best choice.

This seems sensible to me. We link to only the shared objects in the 
acceptance tests, so they should still pick up any problems.