1make: "varmod-loop-delete.mk" line 20: while evaluating variable "VAR" with value "${:U:@VAR@@} rest of the value": while evaluating "${:U:@VAR@@} rest of the value" with value "": Cannot delete variable "VAR" while it is used 2make: Fatal errors encountered -- cannot continue 3make: stopped making "all" in unit-tests 4exit status 1 5