1make: "cond-op-not.mk" line 29: Not empty evaluates to true. 2make: "cond-op-not.mk" line 37: Not space evaluates to false. 3make: "cond-op-not.mk" line 41: Not 0 evaluates to true. 4make: "cond-op-not.mk" line 49: Not 1 evaluates to false. 5make: "cond-op-not.mk" line 55: Not word evaluates to false. 6exit status 0 7