Make the config generate gen_config.h with CFG_ and USE() macros.

Add distclean.  Make clean have double colons so the kconfig makefile's
clean matches.

Makefile

@@ -1,5 +1,37 @@
-all:
+# Makefile for toybox.
-	$(CC) -Wall -Os -s $(CFLAGS) -I . main.c toys/*.c lib/*.c -o toybox
+# Copyright 2006 Rob Landley <rob@landley.net>
 
-clean:
+CFLAGS  = -Wall -Os -s
-	rm toybox
+CC      = $(CROSS_COMPILE)gcc $(CFLAGS)
+HOST_CC = gcc $(CFLAGS)
+
+all: toybox
+
+.PHONY: clean
+
+include kconfig/Makefile
+
+# The long and roundabout sed is to make old versions of sed happy.  New ones
+# have '\n' so can replace one line with two without all the branches and
+# mucking about with hold space.
+gen_config.h: .config
+	sed -n -e 's/^# CONFIG_\(.*\) is not set.*/\1/' \
+	  -e 't notset' -e 'b tryisset' -e ':notset' \
+	  -e 'h' -e 's/.*/#define CFG_& 0/p' \
+	  -e 'g' -e 's/.*/#define USE_&(...)/p' -e 'd' -e ':tryisset' \
+	  -e 's/^CONFIG_\(.*\)=y.*/\1/' -e 't isset' -e 'd' -e ':isset' \
+	  -e 'h' -e 's/.*/#define CFG_& 1/p' \
+	  -e 'g' -e 's/.*/#define USE_&(...) __VA_ARGS__/p' $< > $@
+
+# Actual build
+
+toyfiles = main.c toys/*.c lib/*.c
+toybox: gen_config.h $(toyfiles)
+	$(CC) -Wall -Os -s -funsigned-char $(CFLAGS) -I . \
+		$(toyfiles) -o toybox
+
+clean::
+	rm -f toybox gen_config.h
+
+distclean: clean
+	rm -f .config