The answer is no. I guess nobody has cross-compiled root to the end. I think it should be possible after clearing a number of problems that will appear on the way. The main difficulty, I guess, will be that we need to execute code (rootcling) during the build process.
The first error you have hit (checking for -fPIC) is that -m64 has been added to the CXX flags and is used to check if the option exists.
I believe I need a specific do_configure() step in here. The initial problem was with fortran, hence why I had to link it especially. But I’m going to try adding something like
in the code and see what happens when we get things to configure using the set-up environment within bitbake. Unfortunately, I’m not skilled enough with bitbake to figure out a way to pass in custom build flags outside of the recipe into it (so it gets hard-coded for now).