1
 2all: mid
 3mid: base
 4
 5ifeq ($(midexport),export)
 6mid: export hello=mid
 7else ifeq ($(midexport),unexport)
 8mid: unexport hello=mid
 9else
10mid: hello=mid
11endif
12
13ifeq ($(baseexport),export)
14base: export hello=base
15else ifeq ($(baseexport),unexport)
16base: unexport hello=base
17else
18base: hello=base
19endif
20
21all mid base:; @echo $@ make=$(hello) shell=$$hello