just noticed this is meta-virt layer, file layer.conf:

# The dynamic-layers directory hosts extensions and layer-specific
# modifications.
#
# The .bbappend and .bb files are included if the respective layer
# collection is available.
BBFILES += "${@' '.join('${LAYERDIR}/dynamic-layers/%s/recipes*/*/*.bbappend' % layer \
for layer in BBFILE_COLLECTIONS.split())}"
BBFILES += "${@' '.join('${LAYERDIR}/dynamic-layers/%s/recipes*/*/*.bb' % layer \
for layer in BBFILE_COLLECTIONS.split())}"

BBFILES_DYNAMIC += " \
raspberrypi:${LAYERDIR}/dynamic-layers/raspberrypi/*/*/*.bb \
raspberrypi:${LAYERDIR}/dynamic-layers/rasbperrypi/*/*/*.bbappend \
xilinx:${LAYERDIR}/dynamic-layers/xilinx/*/*/*.bb \
xilinx:${LAYERDIR}/dynamic-layers/xilinx/*/*/*.bbappend \
"

i'm *assuming* that those first two assignments to BBFILES
represent the earlier technique for supporting dynamic layers,
otherwise i'm not sure what they're doing there. with the assignment
to BBFILES_DYNAMIC, is there any value to the earlier assignments?

rday