kbuild: Create Makefile in output dir for *config targets

Upon request from Andi Kleen the Makefile is now created for *config
targets also. So the MAkefile in the output directory is present when
it is expected (after kernel configuration).
Also tell user the Makefile is generated.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Makefile

@@ -379,6 +379,18 @@ RCS_TAR_IGNORE := --exclude SCCS --exclude BitKeeper --exclude .svn --exclude CV
 scripts_basic:
 	$(Q)$(MAKE) $(build)=scripts/basic
 
+.PHONY: outputmakefile
+# outputmakefile generate a Makefile to be placed in output directory, if
+# using a seperate output directory. This allows convinient use
+# of make in output directory
+outputmakefile:
+	$(Q)if /usr/bin/env test ! $(srctree) -ef $(objtree); then \
+	$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile              \
+	    $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL)         \
+	    > $(objtree)/Makefile;                                 \
+	    echo '  GEN    $(objtree)/Makefile';                   \
+	fi
+
 # To make sure we do not include .config for any of the *config targets
 # catch them early, and hand them over to scripts/kconfig/Makefile
 # It is allowed to specify more targets when calling make, including
@@ -423,9 +435,9 @@ ifeq ($(config-targets),1)
 # *config targets only - make sure prerequisites are updated, and descend
 # in scripts/kconfig to make the *config target
 
-config: scripts_basic FORCE
+config: scripts_basic outputmakefile FORCE
 	$(Q)$(MAKE) $(build)=scripts/kconfig $@
-%config: scripts_basic FORCE
+%config: scripts_basic outputmakefile FORCE
 	$(Q)$(MAKE) $(build)=scripts/kconfig $@
 
 else
@@ -711,22 +723,12 @@ $(vmlinux-dirs): prepare-all scripts
 
 .PHONY: prepare-all prepare prepare0 prepare1 prepare2
 
-# prepare 2 generate Makefile to be placed in output directory, if
-# using a seperate output directory. This allows convinient use
-# of make in output directory
-prepare2:
-	$(Q)if /usr/bin/env test ! $(srctree) -ef $(objtree); then \
-	$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile              \
-	    $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL)         \
-	    > $(objtree)/Makefile;                                 \
-	fi
-
-# prepare1 is used to check if we are building in a separate output directory,
+# prepare2 is used to check if we are building in a separate output directory,
 # and if so do:
 # 1) Check that make has not been executed in the kernel src $(srctree)
 # 2) Create the include2 directory, used for the second asm symlink
 
-prepare1: prepare2
+prepare2:
 ifneq ($(KBUILD_SRC),)
 	@echo '  Using $(srctree) as source for kernel'
 	$(Q)if [ -h $(srctree)/include/asm -o -f $(srctree)/.config ]; then \
@@ -738,6 +740,9 @@ ifneq ($(KBUILD_SRC),)
 	$(Q)ln -fsn $(srctree)/include/asm-$(ARCH) include2/asm
 endif
 
+# prepare1 creates a makefile if using a separate output directory
+prepare1: prepare2 outputmakefile
+
 prepare0: prepare1 include/linux/version.h include/asm include/config/MARKER
 ifneq ($(KBUILD_MODULES),)
 	$(Q)rm -rf $(MODVERDIR)