[yocto] use yocto toolchain as external toolchain

[gmane at reliableembeddedsystems.com]

Hi,

It may sound slightly crazy:) but can I use a toolchain, which was 
created by Poky as an external toolchain for Poky?

What I am after is something like this:

I create a multiplatfrom v7 compatible Yocto project, which spits out 
toolchain/rootfs/kernel/various device trees.[1]

Now I need to build for each board a custom u-boot, something like 
[2][3],...

Obviously [2] and [3] build again the toolchain. Would it be possible to 
reuse the toolchain built by [1] like an external toolchain to save some 
build time?

Regards,

Robert


[1] 
https://github.com/RobertBerger/meta-mainline/tree/jethro-training-v4.4.x/multi-v7-ml
[2] 
https://github.com/RobertBerger/meta-mainline/tree/jethro-training-v4.4.x/beagle-bone-black-multi-v7-ml
[3] 
https://github.com/RobertBerger/meta-mainline/tree/jethro-training-v4.4.x/zedboard-multi-v7-ml