arm: include config.h in arch/arm/lib/vectors.S

Commit 41623c91 moved exception handling to arch/arm/lib/vectors.S,
but it missed to include <config.h>.

This mistake causes two problems.

[1]
"enbw_cmc", "da850evm_direct_nor", "calimain" boards are broken.

They expect CONFIG_SYS_DV_NOR_BOOT_CFG (= 0x00000011) at the beginning
of the boot image.

But it is missing since commit 41623c91 because
CONFIG_SYS_DV_NOR_BOOT_CFG is never defined in arch/arm/lib/vectors.S.

[2]
Boards with CONFIG_USE_IRQ fail with undefined reference error
of "IRQ_STACK_START" and "FIQ_STACK_START".

This is _potential_ problem because currently there is no board
enabling CONFIG_USE_IRQ.
But we cannot deny the possibility some board may enable it in future.

(If we are not willing to support interrupt feature, all references
to CONFIG_USE_IRQ should be dropped immediately.)

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Series-to: uboot
Series-version: 2
Series-changes: 2
  - Rephrase commit subject and description. (No change in code-diff)

Cover-letter:
ARM: bug fixes of commit 41623c91 (arch/arm/lib/vectors.S)

END
arm: fix a double-definition error of _start symbol

The symbol "_start" is defined twice in arch/arm/lib/vectors.S:
around line 48 and line 54.

If CONFIG_SYS_DV_NOR_BOOT_CFG is defined (as on calimain board),
build fails:

  arch/arm/lib/vectors.S: Assembler messages:
  arch/arm/lib/vectors.S:54: Error: symbol `_start' is already defined
  make[1]: *** [arch/arm/lib/vectors.o] Error 1
  make: *** [arch/arm/lib] Error 2

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Series-changes: 2
  - No change  (Resend as a series)
kbuild,tools: generate wrapper C sources automatically by Makefile

There are many source files shared between U-boot image and tools.
Instead of adding a lot of dummy wrapper files that just include
the corresponding file in lib/ or common/ directory,
Makefile should automatically generate them.

The original inspiration for this came from
scripts/Makefile.asm-generic of Linux Kernel.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Series-to: uboot
Series-cc: sjg
Series-cc: Charles Manning <cdhmanning@gmail.com>
Series-cc: Gerhard Sittig <gsi@denx.de>
Series-version: 2
Series-changes: 2
  - Rebase on commit 3e1fa221
kbuild: export HOSTCXX and HOSTCXXFLAGS

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>