Have 'avail' not be dependent on 'all'.

There are two reasons for removing this dependency:
- If someone does 'make avail' on the top level Makefile he ends up with
  binaries but without libraries - not nice. Better do just "nothing" and
  have hin understand that he needs to do 'make [all]' on the top level
  Makfile first.
- If 'make avail' is done via 'sudo' it isn't desirable to do a large amount
  of work as root.
BTW: I wasn't sure if this dependency is a good thing in the first place
but I saw it in many examples ('install' depending on 'all') so I did it too.