1make: cond-op-and.mk:36: Variable "UNDEF" is undefined 2make: cond-op-and.mk:41: Variable "UNDEF" is undefined 3make: cond-op-and.mk:44: Variable "UNDEF" is undefined 4make: cond-op-and.mk:60: Unknown operator "&" 5make: cond-op-and.mk:66: Unknown operator "&" 6make: cond-op-and.mk:72: Unknown operator "&" 7make: cond-op-and.mk:78: Unknown operator "&" 8make: cond-op-and.mk:87: Unknown operator "&" 9make: Fatal errors encountered -- cannot continue 10make: stopped in unit-tests 11exit status 1 12