metadata_devices=$(if $(1),$(subst "$(space)","$(comma)",$(strip $(foreach v,$(1),"$(call json_quote,$(v))"))))
metadata_json = \
'{ $(if $(IMAGE_METADATA),$(IMAGE_METADATA)$(comma)) \
+ "metadata_version": "1.0", \
"supported_devices":[$(call metadata_devices,$(1))], \
"version": { \
"dist": "$(call json_quote,$(VERSION_DIST))", \
"version": "$(call json_quote,$(VERSION_NUMBER))", \
"revision": "$(call json_quote,$(REVISION))", \
+ "target": "$(call json_quote,$(TARGETID))", \
"board": "$(call json_quote,$(if $(BOARD_NAME),$(BOARD_NAME),$(DEVICE_NAME)))" \
} \
}'