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