kbuild: bug fixes and cleanups of Makefile.host

This commit imports updates of scripts/Makefile.host
from Linux 3.18-rc1.

Imported commits are:

[1] commit d8d9efe22709 by Masahiro Yamada
  kbuild: fix a typo in scripts/Makefile.host

[2] commit edb950c17de0 by Masahiro Yamada
  kbuild: fix a bug of C++ host program handling

[3] commit 62e2210798ed by Masahiro Yamada
  kbuild: drop shared library support from Makefile.host

[4] commit 663935593915 by Masahiro Yamada
  kbuild: clean up scripts/Makefile.host

[5] commit 1791ff7179f6 by Masahiro Yamada
  kbuild: clean-up and bug fix of scripts/Makefile.host

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cover-letter:
kbuild, kconfig: sync with Linux 3.18-rc1

END
kbuild: improve multi-objs dependency and cleanups

Since Linux 3.18-rc1, Kbuild is able to handle multi-objs
dependency correctly, which also allows us futher cleanups
of some makefiles.

This commit imports those commits:

[1] commit c8589d1e9e01 by Masahiro Yamada
kbuild: handle multi-objs dependency appropriately

[2] commit 97e3226e6e98 by Masahiro Yamada
kbuild: handle the dependency of multi-objs hostprogs appropriately

[3] commit 022af62d0190 by Masahiro Yamada
kbuild: refactor script/kconfig/Makefile

[4] commit 221ecca6cafe by Masahiro Yamada
kbuild: remove redundant clean-files from scripts/kconfig/Makefile

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: sync top Makefile with Linux 3.18-rc1

Since Linux 3.15, relative path feature and related fixes,
cleanups have been merged to the top Makefile.

The relative path feature looks stable enough, so let's import it
to U-Boot along with various cleanups.

Commits imported from Linux (some need adjustment) are:

[1] commit 7e1c04779efd by Michal Marek
  kbuild: Use relative path for $(objtree)

[2] commit 890676c65d69 by Michal Marek
  kbuild: Use relative path when building in the source tree

[3] commit 9da0763bdd82 by Michal Marek
  kbuild: Use relative path when building in a subdir of the source tree

[4] commit c2e28dc975ea by Michal Marek
  kbuild: Print the name of the build directory

[5] commit 066b7ed95580 by Michal Marek
  kbuild: Do not print the build directory with make -s

[6] commit 3f1d9a6cec01 by Michal Marek
  kbuild: make -s should be used with kernelrelease/kernelversion/image_name

[7] commit 7ff525712acf by Masahiro Yamada
  kbuild: fake the "Entering directory ..." message more simply

[8] commit 745a254322c8 by Masahiro Yamada
  kbuild: use $(Q) for sub-make target

[9] commit aa55c8e2f7a3 by Masahiro Yamada
  kbuild: handle C=... and M=... after entering into build directory

[10] commit ab7474ea5361 by Borislav Petkov
  Kbuild: Ignore GREP_OPTIONS env variable

To use relative path feature, tools/Makefile and scripts/Makefile.autoconf
must be tweaked.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kconfig: sync kconfig files with Linux 3.18-rc1

This commit imports Kconfig updates from Linux 3.18-rc1.

'kvmconfig' and 'tinyconfig' help message have been commented out
since they are unavailable at least now;  in the future perhaps
we can implement 'tinyconfig' to disable most of CONFIG_CMD_* to
create a very small U-Boot image.

[1] commit 3aaefce10351 by Josh Triplett
x86, platform, kconfig: move kvmconfig functionality to a helper

[2] commit 0da1d4a0b951 by Josh Triplett
x86: Add "make tinyconfig" to configure the tiniest possible kernel

[3] commit c40724d3f381 by Brian Norris
  kconfig: lxdialog: fix spelling

[4] commit 7285996aa000 by Brian Norris
  kconfig: nconfig: fix multi-byte UTF handling

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: sync misc scripts with Linux 3.18-rc1

This commit imports some updates in misc scripts from Linux 3.18-rc1.

[1] commit cbb4d3e6510b99522719c5ef0 by Horia Geanta
scripts/kernel-doc: handle object-like macros

[2] commit 164f0d2efaaef83 by Michal Marek
kbuild: Fix handling of backslashes in *.cmd files

[3] commit 270a00963cd367214e by Randy Dunlap
scripts/kernel-doc: recognize __meminit

[4] commit a4954fd7724c0f55361eb5 by Masahiro Yamada
  kbuild: remove obj-n and lib-n handling

[5] commit 5b2389b45d1a9c12b9f by Masahiro Yamada
kbuild: simplify build, clean, modbuiltin shorthands

Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: Make scripts executable

The Makefiles call the respective interpreter explicitly, but this makes
it easier to use the scripts manually.

(This commit follows commit 06ed5c2bfaca of Linux Kernel)

Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: drop clang-specific extra warnings

It is true clang has more warnings enabled by default but
Jeroen Hofstee are making lots of efforts to eliminate warnings.
Let's drop clang-related checks and continue to fix C code.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Jeroen Hofstee <jeroen@myspectrum.nl>
kbuild: remove "clobber" target

Now we stick to Linux Kernel's build system, so squash
"clobber" to "clean" target.

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