After a clean install/build of 2.1.5:
0) Although minix.c is missing a "#include mm.h".....
1) modules won't load ("create_module" reports error)
2) can't rebuild modules-2.0.0--compile errors.
3) "tar ztf foo.tgz" fails: "no such file/child returned status 1".
but "gzip -dc foo.tgz | tar xf -" works