MODULES: lib1, main

STEP 0:
    libs: lib1, main
    dirty js modules: lib1, main
    dirty js files:   lib1/l1, lib1/A, main/B, main/m, main/m.export, main
STEP 1:
    libs: lib1, main
    dirty js modules: lib1
    dirty js files:   lib1/A
STEP 2:
    libs: lib1, main
    dirty js modules: lib1
    dirty js files:   lib1/l1, lib1/A
STEP 3:
    libs: lib1, main
    dirty js modules: lib1
    dirty js files:   lib1/l1, lib1/A