First off sorry for rambling on, this is almost brain dump off stuff I've been thinking about..
I can give you an example though thinking about it more it could be achieved with 2 branches. I know more branches adds complexity and maintenance by having to backport between them so having one branch say 'pre-bionic' and just use master for bionic onwards would suffice in this particular case maybe.
A little background on my current LinuxMCE build and to how this came about.
The way I have build LinuxMCE so far is through packer and vagrant, I am used to building in chroot and have no problem with that at all but I thought to extend this further by utilising new container systems so I can move OS easier. This led me back to packer and vagrant.
So far I have been able to build LinuxMCE in VirtualBox, Docker and qemu all through single provisioning scripts wrapping the LinuxMCE build scripts in packer, in theory this could be used to build LinuxMCE in the 'cloud' by whatever provider packer supports.
Granted I have had to take a lot of shortcuts and do a lot of horrible hacks at the moment but I have had a few succesful builds so far.
Docker is probably the fastest method I have tried due to the least overhead, however compiling pthsem fails in the container. VirtualBox while working, is unusable in my opinion for the size of LinuxMCE. Qemu does work but takes a fair few hours to do a complete build on a quad core under kvm but does work great for compiling and providing a functional test environment in vagrant. To model a LinuxMCE network system, even OpenGL with virgl and networking between systems, netboot, disked md etc. I have found this invaluable tool to test LinuxMCE more. I have used lxc in the past but have not tested this path yet but will do so as these are lightweight like a chroot. VMWare and several others are possible.
So after that rambling explanation, it's taking hours to build LinuxMCE under qemu, before I can look at fixing why pthsem fails in docker, I started looking for ways to reduce build time.
On bionic and greater includes debhelper 11. by changing the debhelper requirement in the deb package control and bumping the compat file to 10 most any build that uses the debhelpers should utilise parallel building. I notice when compiling LinuxMCE, on a lot of the builds there is only a single core being utilised so by bumping the debhelper requirements on bionic and onwards, it should speed up build times for a lot of packages.
There are obviously some packages that will need fixing due to this change too, some packages will fail when make is invoked as parallel. some linking methods are different, I think --as-needed flag, so some libs will need juggling around with the link ordering, this is where I stopped, I reverted it because I knew it would break trusty and time better spent elsewhere.
So anyway, back to the original answer a change like this would break pre bionic builds and the only way I see is another branch. Knowing how LinuxMCE deals with this would be useful to move foward.
I can understand the develpoment model and trying not to deviate too much from master across all the branches and having to test across them all.
In the script on packer/vagrant would be trivial to select which build os and then specify which target git branch to build, at the moment I am just feeding in my own tree and have experimented through ways getting the sources into the container and evaluating which methods are faster or portable across providers.
This has been a long journey the last few months but I would like to work on this path more it has really helped me being able to test LinuxMCE across the different versions without having a dedicated box and not touching my working system on 14.04. this came about by looking at ways to make the build faster because it's a little painful inside a vm right now, I would rather take longer and have the build self contained like this though because it has many benefits being able to copy the dev environment around, working on a foreign OS and bringing up the image with only a few commands.
Another option was to look at way to remove pthsem with more updated software that depended on it but it looks like it's used by some core things I cannot test due to lack of knx/eib hardware so that isn't an option currently for me.
Just thinking of ways to improve LinuxMCE, I know extra branches equals more effort and time is the enemy but I don't want to break backwards compatilbility either, I think you guys and girls have done a stellar job and the current system works great. I hope you not think I'm poking holes at LinuxMCE just I think with packer/vagrant it is how one would set up machines manually so by me wrapping this, eventually those wiki pages "building LinuxMCE" could be redundant. It could be codified and at the end of a couple packer commands out pops a (HUGE) machine image with dev environment and built deb packages, and from then even various machine images, like core, hybrid etc. can be made. At the moment I am looking at ways to get my database changes in using this method but I am not going to lie I am struggling with LinuxMCE as you can well imagine.
I would like to know more about how you work and how this all fits because I do not want to interfere with current build methods, so I am trying to make this an extension if you like, a wrapper around the buildscripts. I would welcome and help with this I don't want to waste your time the only thing stopping me uploading at the moment is it being so rough and cutting corners but I hope to work these out.
If you can make sense of this rambling posts and weird bug reports there is some method to my madness I hope
Cheers.
P.S. While I think of it, I have just managed to install a hybrid in vagrant with the debs from deb.linuxmce.org, I got access the vm by disabling the firewall in /etc/pluto.conf with a hack in the Vagrantfile but this is hardly optimal so wondered if there was a way to enable ssh access by the cli after apt install lmce-mybrid. the firewall comes up and blocks access so i had to disable the firewall because I don't know how to enable programmatically, the outside ssh access in LinuxMCE settings to stick. Phew. Thanks!
