[yocto] call custom sh script in do_compile

[Mircea Gliga]

Hello

I have a build.sh script used to build outside yocto, after sourcing the 
build environment.
I want to use the same build.sh script inside the recipe, in the 
do_compile task, something like:

do_compile () {

  ./build.sh ${MACHINE}
}

The build.sh script eventually calls make for several targets, release 
debug etc...
The idea with this script is to be used both inside yocto and outside 
(after sourcing
build/tmp/environment-setup-cortexa5hf-neon-poky-linux-gnueabi), by 
reusing the code.

What is the proper way to use a custom shell script to build things ?
How to pass info from oe_runmake/EXTRA_OEMAKE ?

Thanks
Mircea