1 make: "directive-ifmake.mk" line 13: ok: positive condition works
2 make: "directive-ifmake.mk" line 24: ok: negation works
3 make: "directive-ifmake.mk" line 33: ok: double negation works
4 make: "directive-ifmake.mk" line 40: ok: both mentioned
5 make: "directive-ifmake.mk" line 47: ok: only those mentioned
6 make: "directive-ifmake.mk" line 57: Targets can even be added at parse time.
7 make: "directive-ifmake.mk" line 75: ok