[yocto] The BitBake equivalent of "Hello, World!"

[Tomas Frydrych]

>> Tasks must be Python functions. 
>>         
>>
> No, they can be shell functions too.

Probably worth adding that if you are doing an _append() on a task
function, you have to match the original function type. E.g., if you
want to append a shell snippet to a python task function, you need to do
something like this (from the eglibc recipe):

do_unpack_append() {
    bb.build.exec_func('do_move_ports', d)
}

do_move_ports() {
        if test -d ${WORKDIR}/${EGLIBC_BRANCH}/ports ; then
	    rm -rf ${S}/ports
	    mv ${WORKDIR}/${EGLIBC_BRANCH}/ports ${S}/
	fi
}

Tomas