oeqa does not have general access to d variable context and needs to
determine parallel make settings.
Extract the code from parallel_make into reusable parallel_make_value.
Also correct function description of return value from None to empty
string.
(From OE-Core rev: c8670e9c7db565401412dad979c2ee53a586b59d)
Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
ed49517562