Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild

Merge git://git./linux/kernel/git/sam/kbuild

* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild: (40 commits)
  kbuild: introduce ccflags-y, asflags-y and ldflags-y
  kbuild: enable 'make CPPFLAGS=...' to add additional options to CPP
  kbuild: enable use of AFLAGS and CFLAGS on commandline
  kbuild: enable 'make AFLAGS=...' to add additional options to AS
  kbuild: fix AFLAGS use in h8300 and m68knommu
  kbuild: check for wrong use of CFLAGS
  kbuild: enable 'make CFLAGS=...' to add additional options to CC
  kbuild: fix up CFLAGS usage
  kbuild: make modpost detect unterminated device id lists
  kbuild: call export_report from the Makefile
  kbuild: move Kai Germaschewski to CREDITS
  kconfig/menuconfig: distinguish between selected-by-another options and comments
  kconfig: tristate choices with mixed tristate and boolean values
  include/linux/Kbuild: remove duplicate entries
  kbuild: kill backward compatibility checks
  kbuild: kill EXTRA_ARFLAGS
  kbuild: fix documentation in makefiles.txt
  kbuild: call make once for all targets when O=.. is used
  kbuild: pass -g to assembler under CONFIG_DEBUG_INFO
  kbuild: update _shipped files for kconfig syntax cleanup
  ...

Fix up conflicts in arch/um/sys-{x86_64,i386}/Makefile manually.