I went from 12.04 to 16.04. I skipped 14.04 because of the DE which I couldn't bend to my will. I remember that I had similar problems in the last months on 12.04, with some new versions of some programs unavailable on 12.04. I guess that I could have installed them in a 14.04 docker container (would the kernel version have been ok?) Maybe you can do the same for a compiler. I don't know if it would be convenient. I'm more into scripting languages and I use gcc directly only every other year or more, so no big deal for me.