I applied the patches mentioned here because I used GCC 8.1 on the Odroid-U2 SoC too. I guess these three patches would not be needed for GCC < 8, and it would just work.
Concerning cross-compiling, it’s certainly a good idea, I’ll dig into that when I find some time.
Concerning AppLauncher to be built locally, I understand that both with native or cross-compiling, the current cmake file does not build AppLauncher yet, it should be modified to download sources etc… and this is well beyond my skills.