----- cga5ext_2018.11.bb:
// SRC_URI = someurl with buildtools
...
inherit cross bin_package relocatable
...
python() {
 d.setVar("CGA5EXT_HOST_PREFIX", "arm-buildroot-linux-gnueabi-")
}
...
BBCLASSEXTEND = "nativesdk"

----- draminit~.0.1.bb:
TOOLCHAIN="cga5ext"