Empty variable treated as undefined

[Pawlowsky, Marc]

If a variable has an empty value ifndef will enter the true branch.



> make EMPTY=0 all 
echo anything
anything
> make EMPTY=1 all 
makefile:12: *** variable is defined..  Stop.
> cat makefile
ifeq (1,${EMPTY})
  VAR=
else
  VAR=anything
endif

ifndef VAR
  VAR=${error variable is defined.}
endif

all:
        echo ${VAR}


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