make: Unknown modifier 'Z'
make: "cond-token-string.mk" line 12: Malformed conditional ("" != "${:Uvalue:Z}")
make: "cond-token-string.mk" line 21: xvalue is not defined.
make: "cond-token-string.mk" line 27: Malformed conditional (x${:Uvalue} == "")
make: "cond-token-string.mk" line 34: Expected.
make: Fatal errors encountered -- cannot continue
make: stopped in unit-tests
exit status 1