# ==========================================================================
  # Cleaning up
  # ==========================================================================
  
  src := $(obj)

  PHONY := __clean

  __clean:

  # Shorthand for $(Q)$(MAKE) scripts/Makefile.clean obj=dir
  # Usage:
  # $(Q)$(MAKE) $(clean)=dir
  clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj

  # The filename Kbuild has precedence over Makefile

  kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
  include $(if $(wildcard $(kbuild-dir)/Kbuild), $(kbuild-dir)/Kbuild, $(kbuild-dir)/Makefile)

  
  # Figure out what we need to build from the various variables
  # ==========================================================================
  
  __subdir-y	:= $(patsubst %/,%,$(filter %/, $(obj-y)))
  subdir-y	+= $(__subdir-y)
  __subdir-m	:= $(patsubst %/,%,$(filter %/, $(obj-m)))
  subdir-m	+= $(__subdir-m)
  __subdir-n	:= $(patsubst %/,%,$(filter %/, $(obj-n)))
  subdir-n	+= $(__subdir-n)
  __subdir-	:= $(patsubst %/,%,$(filter %/, $(obj-)))
  subdir-		+= $(__subdir-)
  
  # Subdirectories we need to descend into
  
  subdir-ym	:= $(sort $(subdir-y) $(subdir-m))
  subdir-ymn      := $(sort $(subdir-ym) $(subdir-n) $(subdir-))
  
  # Add subdir path
  
  subdir-ymn	:= $(addprefix $(obj)/,$(subdir-ymn))
  
  # build a list of files to remove, usually releative to the current
  # directory
  
  __clean-files	:= $(extra-y) $(EXTRA_TARGETS) $(always) \
  		   $(targets) $(clean-files)             \
  		   $(host-progs)                         \
  		   $(hostprogs-y) $(hostprogs-m) $(hostprogs-)
  
  # as clean-files is given relative to the current directory, this adds
  # a $(obj) prefix, except for absolute paths
  
  __clean-files   := $(wildcard                                               \
                     $(addprefix $(obj)/, $(filter-out /%, $(__clean-files))) \
  		   $(filter /%, $(__clean-files)))
  
  # as clean-dirs is given relative to the current directory, this adds
  # a $(obj) prefix, except for absolute paths
  
  __clean-dirs    := $(wildcard                                               \
                     $(addprefix $(obj)/, $(filter-out /%, $(clean-dirs)))    \
  		   $(filter /%, $(clean-dirs)))
  
  # ==========================================================================
  
  quiet_cmd_clean    = CLEAN   $(obj)
        cmd_clean    = rm -f $(__clean-files)
  quiet_cmd_cleandir = CLEAN   $(__clean-dirs)
        cmd_cleandir = rm -rf $(__clean-dirs)
  
  
  __clean: $(subdir-ymn)
  ifneq ($(strip $(__clean-files)),)
  	+$(call cmd,clean)
  endif
  ifneq ($(strip $(__clean-dirs)),)
  	+$(call cmd,cleandir)
  endif
  ifneq ($(strip $(clean-rule)),)
  	+$(clean-rule)
  endif
  	@:
  
  
  # ===========================================================================
  # Generic stuff
  # ===========================================================================
  
  # Descending
  # ---------------------------------------------------------------------------

  PHONY += $(subdir-ymn)

  $(subdir-ymn):
  	$(Q)$(MAKE) $(clean)=$@
  
  # If quiet is set, only print short version of command
  
  cmd = @$(if $($(quiet)cmd_$(1)),echo '  $($(quiet)cmd_$(1))' &&) $(cmd_$(1))

  
  
  # Declare the contents of the .PHONY variable as phony.  We keep that
  # information in a variable se we can use it in if_changed and friends.
  
  .PHONY: $(PHONY)