kbuild: Introduced build-targets

build-targets is used to list targets that is always built.
This allowed misuse of EXTRA_TARGETS to be deleted.
built-in.o is now only created for directories defining a obj-* variable,
avoiding this for scripts and lxdialog

One Makefile needed a dummy obj- statement

Makefile

@@ -629,7 +629,7 @@ xconfig: scripts/kconfig/qconf
 	./scripts/kconfig/qconf arch/$(ARCH)/Kconfig
 
 menuconfig: scripts/kconfig/mconf
-	$(Q)$(MAKE) -f scripts/Makefile.build obj=scripts lxdialog
+	$(Q)$(MAKE) -f scripts/Makefile.build obj=scripts/lxdialog
 	./scripts/kconfig/mconf arch/$(ARCH)/Kconfig
 
 config: scripts/kconfig/conf

drivers/misc/Makefile

 #
 # Makefile for misc devices that really don't fit anywhere else.
 #
-
+obj- := misc.o	# Dummy rule to force built-in.o to be made
 include $(TOPDIR)/Rules.make

scripts/Makefile

@@ -8,31 +8,12 @@
 # docproc: 	 Preprocess .tmpl file in order to generate .sgml documentation
 # conmakehash:	 Create arrays for initializing the kernel console tables
 
-EXTRA_TARGETS := fixdep split-include docproc conmakehash
-
-subdir-	:= lxdialog kconfig
-
-# Yikes. We need to build this stuff here even if the user only wants
-# modules.
-
-KBUILD_BUILTIN := 1
-
-# The following temporary rule will make sure that people's
-# trees get updated to the right permissions, since patch(1)
-# can't do it
-# ---------------------------------------------------------------------------
-
 host-progs    := fixdep split-include conmakehash docproc
+build-targets := $(host-progs)
 
-include $(TOPDIR)/Rules.make
-
-
-# ---------------------------------------------------------------------------
-# Targets hardcoded and wellknow in top-level makefile
-.PHONY: lxdialog
-lxdialog:
-	$(call descend,scripts/lxdialog,)
+# Let clean descend into subdirs
+subdir-	:= lxdialog kconfig
 
 # fixdep is needed to compile other host programs
 $(obj)/split-include $(obj)/docproc \
-$(obj)/conmakehash lxdialog: $(obj)/fixdep
+$(obj)/conmakehash: $(obj)/fixdep

scripts/Makefile.build

@@ -40,12 +40,14 @@ endif
 ifdef L_TARGET
 L_TARGET := $(obj)/$(L_TARGET)
 else
+ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-)),)
 O_TARGET := $(obj)/built-in.o
 endif
+endif
 
 __build: $(if $(KBUILD_BUILTIN),$(O_TARGET) $(L_TARGET) $(EXTRA_TARGETS)) \
 	 $(if $(KBUILD_MODULES),$(obj-m)) \
-	 $(subdir-ym)
+	 $(subdir-ym) $(build-targets)
 	@:
 
 # Compile C sources (.c)

scripts/Makefile.lib

@@ -92,6 +92,7 @@ host-cshobjs	:= $(sort $(foreach m,$(host-cshlib),$($(m:.so=-objs))))
 # Add subdir path
 
 EXTRA_TARGETS	:= $(addprefix $(obj)/,$(EXTRA_TARGETS))
+build-targets	:= $(addprefix $(obj)/,$(build-targets))
 obj-y		:= $(addprefix $(obj)/,$(obj-y))
 obj-m		:= $(addprefix $(obj)/,$(obj-m))
 export-objs	:= $(addprefix $(obj)/,$(export-objs))

scripts/lxdialog/Makefile

@@ -16,18 +16,14 @@ endif
 endif
 
 host-progs    := lxdialog
+build-targets := $(host-progs)
 
 lxdialog-objs := checklist.o menubox.o textbox.o yesno.o inputbox.o \
 		 util.o lxdialog.o msgbox.o
 
-EXTRA_TARGETS := lxdialog
-
 first_rule: ncurses
 
-include $(TOPDIR)/Rules.make
-
 .PHONY: ncurses
-
 ncurses:
 	@echo "main() {}" > lxtemp.c
 	@if $(HOSTCC) lxtemp.c  $(HOST_LOADLIBES); then \