Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

Pull kbuild updates from Michal Marek:
 - make clean also considers $(extra-m) and $(extra-) to be consistent
 - cleanup and fixes in scripts/Makefile.host
 - allow to override the name of the Python 2 executable with make
   PYTHON=... (only needed for ia64 in practice)
 - option to split debugingo into *.dwo files to save disk space if the
   compiler supports it (CONFIG_DEBUG_INFO_SPLIT)
 - option to use dwarf4 debuginfo if the compiler supports it
   (CONFIG_DEBUG_INFO_DWARF4)
 - fix for disabling certain warnings with clang
 - fix for unneeded rebuild with dash when a command contains
   backslashes

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  kbuild: Fix handling of backslashes in *.cmd files
  kbuild, LLVMLinux: Supress warnings unless W=1-3
  Kbuild: Add a option to enable dwarf4 v2
  kbuild: Support split debug info v4
  kbuild: allow to override Python command name
  kbuild: clean-up and bug fix of scripts/Makefile.host
  kbuild: clean up scripts/Makefile.host
  kbuild: drop shared library support from Makefile.host
  kbuild: fix a bug of C++ host program handling
  kbuild: fix a typo in scripts/Makefile.host
  scripts/Makefile.clean: clean also $(extra-m) and $(extra-)

diff --cc Documentation/kbuild/makefiles.txt
Simple merge

diff --cc Makefile
index a897c50db515d7adf8dec34f7c3298c9988be953,4aef4f8612382117f837decac4ee7e45080fe387..ada00f0d2a11730746f87e4ff5213eb2819c827d
--- 1/Makefile
--- 2/Makefile
+++ b/Makefile
@@@ -707,12 -684,17 +709,19 @@@ KBUILD_CFLAGS   += -fomit-frame-pointe
  endif
  endif
  
 +KBUILD_CFLAGS   += $(call cc-option, -fno-var-tracking-assignments)
 +
  ifdef CONFIG_DEBUG_INFO
+ ifdef CONFIG_DEBUG_INFO_SPLIT
+ KBUILD_CFLAGS   += $(call cc-option, -gsplit-dwarf, -g)
+ else
  KBUILD_CFLAGS += -g
+ endif
  KBUILD_AFLAGS += -Wa,-gdwarf-2
  endif
+ ifdef CONFIG_DEBUG_INFO_DWARF4
+ KBUILD_CFLAGS += $(call cc-option, -gdwarf-4,)
+ endif
  
  ifdef CONFIG_DEBUG_INFO_REDUCED
  KBUILD_CFLAGS         += $(call cc-option, -femit-struct-debug-baseonly) \

diff --cc lib/Kconfig.debug
Simple merge