make -f varmod-loop-delete.mk delete-active-variable || true
make: varmod-loop-delete.mk:31: Cannot delete variable "VAR" while it is used
	while evaluating "${:U:@VAR@@} rest of the value" with value ""
	while evaluating variable "VAR" with value "${:U:@VAR@@} rest of the value"
	in make[1] in directory "<curdir>"
make: Fatal errors encountered -- cannot continue
make: stopped making "delete-active-variable" in unit-tests

make -f varmod-loop-delete.mk delete-active-variable-in-target || true
: delete-active-variable-in-target: ' rest of the value'

exit status 0

.