[yocto] [Pyro] Multiple toolchains

[philippe gislard]

Hello,

We are updating our BSP from Krogoth to Pyro.
We are using a kernel designed and patched specifically for our
hardware (3.10.40) that does not compile with GCC 5.x or GCC6.x.
AFAIK, Pyro is qualified with GCC 5.x and GCC6.x (not with earlier versions).

What is the easiest way to use two toolchains?
- GCC 4.9 for the kernel.
- GCC 6.3 for the other packages.

Thank you.

-- 
Philippe GISLARD