Abort makefile if variable not set

Question

How could I abort a make/makefile execution based on a makefile\'s variable not being set/valued?

I came up with this, but works only if caller doesn\'t explicitly r

Answer 1

Use the shell function test:

foo:
    test $(something)

Usage:

$ make foo
test 
Makefile:2: recipe for target 'foo' failed
make: *** [foo] Error 1
$ make foo something=x
test x