#!/bin/sh

  # SPDX-License-Identifier: GPL-2.0

  # Generates a small Makefile used in the root of the output
  # directory, to allow make to be started from there.
  # The Makefile also allow for more convinient build of external modules
  
  # Usage
  # $1 - Kernel src directory
  # $2 - Output directory
  # $3 - version
  # $4 - patchlevel

  test ! -r $2/Makefile -o -O $2/Makefile || exit 0

  # Only overwrite automatically generated Makefiles
  # (so we do not overwrite kernel Makefile)

  if test -e $2/Makefile && ! grep -q Automatically $2/Makefile

  then
  	exit 0
  fi

  if [ "${quiet}" != "silent_" ]; then
  	echo "  GEN     $2/Makefile"
  fi

  
  cat << EOF > $2/Makefile

  # Automatically generated by $0: don't edit
  
  VERSION = $3
  PATCHLEVEL = $4

  lastword = \$(word \$(words \$(1)),\$(1))
  makedir := \$(dir \$(call lastword,\$(MAKEFILE_LIST)))

  ifeq ("\$(origin V)", "command line")
  VERBOSE := \$(V)
  endif
  ifneq (\$(VERBOSE),1)
  Q := @
  endif

  MAKEARGS := -C $1
  MAKEARGS += O=\$(if \$(patsubst /%,,\$(makedir)),\$(CURDIR)/)\$(patsubst %/,%,\$(makedir))

  
  MAKEFLAGS += --no-print-directory

  .PHONY: __sub-make \$(MAKECMDGOALS)

  __sub-make:
  	\$(Q)\$(MAKE) \$(MAKEARGS) \$(MAKECMDGOALS)

  \$(filter-out __sub-make, \$(MAKECMDGOALS)): __sub-make

  	@:

  EOF