nullstring =
space = $(nullstring) # <- notice the trailing space (only leading is stripped)

suitepairs = $(foreach suite,wheezy jessie,$(suite)-deprecated:$(suite))
suitepairs += wheezy:jessie jessie:stretch
suites = $(sort $(subst :,$(space),$(suitepairs)))

all: symlinkfarm

symlinkfarm:
	$(foreach pair,$(suitepairs),\
	shtool mkshadow $(subst :,$(space),$(pair)) 2>/dev/null;)

clean:
	find * -type l -delete
	find * -empty -delete
