This patch replaces the main Linux kernel makefile, removing lots of clutter
which keep kconfig from being built stand-alone. It was taken from
https://github.com/lacombar/kconfig/blob/kconfig-sa-2.6.39/Makefile

The only manual change: -DCONFIG_=\"\" was added to HOSTCFLAGS because we need
it that way for Freetz.

--- Makefile
+++ Makefile
@@ -0,0 +1,100 @@
+VERSION = 5
+PATCHLEVEL = 18
+SUBLEVEL = 0
+EXTRAVERSION =
+NAME = "Linux for Workgroups"
+
+# To put more focus on warnings, be less verbose as default
+# Use 'make V=1' to see the full commands
+
+ifeq ("$(origin V)", "command line")
+  KBUILD_VERBOSE = $(V)
+endif
+ifndef KBUILD_VERBOSE
+  KBUILD_VERBOSE = 0
+endif
+
+srctree		:= $(if $(KBUILD_SRC),$(KBUILD_SRC),$(CURDIR))
+objtree		:= $(CURDIR)
+
+export srctree objtree
+
+CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
+	  else if [ -x /bin/bash ]; then echo /bin/bash; \
+	  else echo sh; fi ; fi)
+
+HOSTCC       = gcc
+HOSTCXX      = g++
+HOSTCFLAGS   = -Wall -Wno-char-subscripts -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -DCONFIG_=\"\"
+HOSTCXXFLAGS = -O2
+
+export CONFIG_SHELL HOSTCC HOSTCXX HOSTCFLAGS HOSTCXXFLAGS
+
+# Beautify output
+# ---------------------------------------------------------------------------
+#
+# Normally, we echo the whole command before executing it. By making
+# that echo $($(quiet)$(cmd)), we now have the possibility to set
+# $(quiet) to choose other forms of output instead, e.g.
+#
+#         quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@
+#         cmd_cc_o_c       = $(CC) $(c_flags) -c -o $@ $<
+#
+# If $(quiet) is empty, the whole command will be printed.
+# If it is set to "quiet_", only the short version will be printed. 
+# If it is set to "silent_", nothing will be printed at all, since
+# the variable $(silent_cmd_cc_o_c) doesn't exist.
+#
+# A simple variant is to prefix commands with $(Q) - that's useful
+# for commands that shall be hidden in non-verbose mode.
+#
+#	$(Q)ln $@ :<
+#
+# If KBUILD_VERBOSE equals 0 then the above command will be hidden.
+# If KBUILD_VERBOSE equals 1 then the above command is displayed.
+
+ifeq ($(KBUILD_VERBOSE),1)
+  quiet =
+  Q =
+else
+  quiet=quiet_
+  Q = @
+endif
+export quiet Q KBUILD_VERBOSE
+
+# We need some generic definitions (do not try to remake the file).
+include $(srctree)/scripts/Kbuild.include
+
+# Basic helpers built in scripts/
+PHONY += scripts_basic
+scripts_basic:
+	$(Q)$(MAKE) $(build)=scripts/basic
+	$(Q)rm -f .tmp_quiet_recordmcount
+
+config: scripts_basic FORCE
+	$(Q)$(MAKE) $(build)=scripts/kconfig $@
+
+%config: scripts_basic FORCE
+	$(Q)$(MAKE) $(build)=scripts/kconfig $@
+
+# mrproper - Delete all generated files, including .config
+#
+mrproper-dirs      := $(addprefix _mrproper_,scripts)
+
+PHONY += $(mrproper-dirs) mrproper
+$(mrproper-dirs):
+	$(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@)
+
+mrproper: $(mrproper-dirs)
+
+# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=dir
+# Usage:
+# $(Q)$(MAKE) $(clean)=dir
+clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj
+
+PHONY += FORCE
+FORCE:
+
+# Declare the contents of the .PHONY variable as phony.  We keep that
+# information in a variable so we can use it in if_changed and friends.
+.PHONY: $(PHONY)