kconfig: make localmodconfig to run streamline_config.pl

Running the streamline_config.pl script manually can still be confusing
for some users. This patch adds the localmodconfig option. This will
automatically run streamline_config.pl on the current .config and
then run "make silentoldconfig" to fix any wholes that might have been
created.

 $ make localmodconfig

This will remove any module configurations in .config that are not needed
to compile the modules that are loaded.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

scripts/kconfig/Makefile

@@ -2,7 +2,8 @@
 # Kernel configuration targets
 # These targets are used from top-level makefile
 
-PHONY += oldconfig xconfig gconfig menuconfig config silentoldconfig update-po-config
+PHONY += oldconfig xconfig gconfig menuconfig config silentoldconfig update-po-config \
+	localmodconfig
 
 ifdef KBUILD_KCONFIG
 Kconfig := $(KBUILD_KCONFIG)
@@ -28,6 +29,15 @@ oldconfig: $(obj)/conf
 silentoldconfig: $(obj)/conf
 	$< -s $(Kconfig)
 
+localmodconfig: $(obj)/streamline_config.pl $(obj)/conf
+	$(Q)perl $< $(Kconfig) > .tmp.config
+	$(Q)cmp -s .tmp.config .config ||		\
+		(mv -f .config .config.old.1;		\
+		 mv -f .tmp.config .config;		\
+		 $(obj)/conf -s $(Kconfig);		\
+		 mv -f .config.old.1 .config.old)
+	$(Q)rm -f .tmp.config
+
 # Create new linux.pot file
 # Adjust charset to UTF-8 in .po file to accept UTF-8 in Kconfig files
 # The symlink is used to repair a deficiency in arch/um
@@ -83,6 +93,7 @@ help:
 	@echo  '  xconfig	  - Update current config utilising a QT based front-end'
 	@echo  '  gconfig	  - Update current config utilising a GTK based front-end'
 	@echo  '  oldconfig	  - Update current config utilising a provided .config as base'
+	@echo  '  localmodconfig  - Update current config disabling modules not loaded'
 	@echo  '  silentoldconfig - Same as oldconfig, but quietly, additionally update deps'
 	@echo  '  randconfig	  - New config with random answer to all options'
 	@echo  '  defconfig	  - New config with default answer to all options'