The package needs to have a recipe available that when built with bitbake to offer no errors and the proper configuration.
There is a recipe available on meta-networking: http://cgit.openembedded.org/cgit.cgi/meta-openembedded/tree/meta-networking/recipes-support/ifenslave/ifenslave_1.1.0.bb?h=master Tried this package and it builds for qemuppc. The patch remains to be made available in the image.
Verified by building with no additional errors.