U-Boot has imported various source files from other projects,
mostly Linux.

Something like

  #ifdef __UBOOT__
    [ modification for U-Boot ]
  #else
    [ original code ]
  #endif

is an often used strategy for clarification of adjusted parts,
that is, easier re-sync in future.

Instead of defining __UBOOT__ in each source file,
passing it from the top Makefile would be easier.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>

resync with linux:

commit 455c6fdbd219161bd09b1165f11699d6d73de11c
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun Mar 30 20:40:15 2014 -0700

    Linux 3.14

Needed for the MTD/UBI/UBIFS resync

Just copied the files from Linux, changed the license file header,
and add in the c-file:

+#define __UBOOT__
 #include <linux/rbtree_augmented.h>
+#ifndef __UBOOT__
 #include <linux/export.h>
+#else
+#include <ubi_uboot.h>
+#endif

so, it compiles for U-Boot.

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Marek Vasut <marex@denx.de>
Cc: Sergey Lapin <slapin@ossfans.org>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Tom Rini <trini@ti.com>

Signed-off-by: Wolfgang Denk <wd@denx.de>
[trini: Fixup common/cmd_io.c]
Signed-off-by: Tom Rini <trini@ti.com>

Now that the other architecture-specific lib directories have been
moved out of the top-level directory there's not much reason to have the
'_generic' suffix on the common lib directory.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

Now it's used at UBI module. Of course other modules can use it.
If you want to use it, please define CONFIG_RBTREE

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>