[PATCH] uml kbuild: avoid useless rebuilds

- 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: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/kernel/tt/Makefile

@@ -4,6 +4,7 @@
 #
 
 extra-y := unmap_fin.o
+targets := unmap.o
 clean-files := unmap_tmp.o
 
 obj-y = exec_kern.o exec_user.o gdb.o ksyms.o mem.o mem_user.o process_kern.o \