MODULES: lib1, main

STEP 0:
    libs: lib1, main
    dirty js modules: lib1, main
    dirty js files:   lib1/l1_0, lib1/l1_1, main/m, main/m.export
STEP 1:
    libs: lib1, main
    dirty js modules: lib1
STEP 2:
    libs: lib1, main