How to change gcc from clang at build kernel and world?

[Mori Hiroki]

Hi.

I make support Eventtimer and FDT and INTRNG to cns11xx code.

This is almost done. But hang up at init. I think it's a interrupt issue.

https://gist.github.com/yamori813/ae047a28a825aac255e436fd8ccaf785


https://github.com/yamori813/freebsd/tree/zrouter/sys/arm/cavium/cns11xx


cns11xx is arm4(not arm4t).  arm build on head is change to use clang
several month ago. I want use gcc at buildworld and buildkernel.

Because of clang use bx instruction. bx instruction not support arm4.

How do I change to gcc from clang?

I found bx instruction at 

contrib/compiler-rt/lib/builtins/arm/

It must be changed bx to mov instruction.

Regards.

Hiroki Mori