FWIW it's a relatively new feature: when PACKAGECONFIG is evaluated it writes the enabled/disabled values to PACKAGECONFIG_CONFARGS, which classes can then use to set the relevant variable.  For now it also sets EXTRA_OECONF but that was meant to be changed now that we're unfrozen.

Martin, would you be able to write and test the change to remove EXTRA_OECONF from the PACKAGECONFIG handling?

Ross