final batch of kbuild updates

Hi Linus.

Here follows the final batch of kbuild updates for the merge window.

Highlights:

o We no longer let sparse warm about void-valued expressions
o We have implmented additional checks on out user space headers We do not fail on these yet - there are to much to be fixed.
o Added some long needed documentation for kconfig and kbuild Always room for more - especially on the kbuild parts.

This set includes a fix in the m68k specific Kconfig file - this is acked by Gert.

The kconfig changes is mostly adding comments. The actual changes will wait until next merge window.

Please pull from:

git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next.git master

Sam

Hannes Eder (1):
kbuild: disable sparse warning "returning void-valued expression"

Mike Frysinger (2):
headers_check.pl: disallow extern's
kbuild: in headers_install autoconvert asm/inline/volatile to __xxx__

Randy Dunlap (1):
kbuild: make *config usage docs

Sam Ravnborg (10):
m68k: fix recursive dependency in Kconfig
kconfig: explain symbol value defaults
kconfig: add comments to symbol flags
kconfig: struct property commented
kconfig: improve error messages for bad source statements
kbuild: check for leaked CONFIG_ symbols to userspace
kbuild: document environment variables
kbuild: drop debugging leftover in tags.sh
kbuild: add checks for include of linux/types in userspace headers
kbuild: ignore a few files in headers_check

 Documentation/kbuild/00-INDEX       |    6 +-
 Documentation/kbuild/kbuild.txt     |  126 +++++++++++++++++++++++
 Documentation/kbuild/kconfig.txt    |  188 +++++++++++++++++++++++++++++++++++
 Makefile                            |    3 +-
 README                              |   32 ++++---
 arch/m68k/Kconfig                   |    1 -
 scripts/headers_check.pl            |   70 +++++++++++++-
 scripts/headers_install.pl          |    3 +
 scripts/kconfig/expr.h              |   82 ++++++++++-----
 scripts/kconfig/lex.zconf.c_shipped |    7 +-
 scripts/kconfig/zconf.l             |    7 +-
 scripts/tags.sh                     |    1 -
 12 files changed, 476 insertions(+), 50 deletions(-)