@nathanchance thx for great work
But how to build kernel with gcc 9.2.0
could you please add manual for that
However, compiling with GCC 9.2.0 is the same as compiling with GCC 4.9.4, you point the CROSS_COMPILE variable at the GCC 9.2.0 toolchain (or use PATH and update the CROSS_COMPILE prefix to match) and go from there. There are probably going to be new warnings that you will need to solve and there are potentially some other commits that you will need to pick to get a boot off.
If anyone else wants to pitch in and write something up, I'd be happy to add it to the OP.