'Prerequisite Checking' within the build system

$ diff ./include/subdir.mk ./include/subdir.mk.bak
45a46

env time -f "time: $(1)$(if $(4),/$(4))/$(if $(3),$(3)-)$(2)#%U#%S#%e" -- \

delete the displayed line from ./include/subdir.mk

and delete these 4 lines from the file shown above

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have you seen this