- Fix some problems with usage of $(targets) (sometimes missing, sometimes
  used badly) that trigger partial rebuilds when doing a rebuild.

- At that purpose, also factor out some common code for symlinks creation.

- Fix a x86-64 build warning, caused by -L/usr/lib, which is anyway useless,
  and invalid in the x86-64 case.

Tested on x86_64 and x86.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>