Mission accomplished! 
I gave Linux Mint 18.3 a try and it did it because of the newer packages, so if anybody plans to crosscompile leia on pc for vero, i’d consider to take the latest Ubuntu or Linux Mint, because they are the same. I’ve spent 3 days to figure it out, but now my first package is lying in the path!
Qemu packages i’ll build in an vm first, but the main thing was getting leia out of pc. 
Next thing will be to get rid of that annoying syscall-thing.
My bad, it’s no crosscompile-toolchain, that’s all, took a while to get used to the build-system. 
Solution: [HowTo] Emulating Debian Stretch arm64 on a x86_64 Linux host
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