I finally managed to get it running, it turned out that FreeBSD is more picky about my CFLAGS then linux is, so it kept breaking.
It’s nice to finally have it running again, now I can even start doing some work on it 
Since the 5.4 profile has been removed, I decided it was time to do the long-awaited (by me) reinstall of my devevelopment box.
It has been running my test server with apache, mysql, bugzilla, bugday devsite, phpmyadmin etc. without any nonfixable problems, so I’ll call it a success story, great work Gentoo/ALT team (at least for not banning me 
)
So I’m in the process of installing 6.0, but it’s behaving weird (sh processes not shutting down, and hitting the process limit), but I have a feeling that it will work out.