1 level 1: variable 0, env 1 2 level 2: variable 1, env 2 3 level 3: variable 2, env 3 4 : set-env-same 5 ok 6 : set-env-different 7 make: Cannot override read-only global variable ".MAKE.LEVEL.ENV" with a command line variable 8 in make[1] in directory "<curdir>" 9 make: Fatal errors encountered -- cannot continue 10 make: stopped making "ok" in unit-tests 11 set-env-different: exit 1 12 exit status 0 13