kconfig: refactor ncurses package checks for building mconf and nconf

The mconf (or its infrastructure, lxdiaglog) depends on the ncurses.
Move and rename check-lxdialog.sh to mconf-cfg.sh to make it work in
the same way as for qconf and gconf.

This commit fixes some more weirdnesses.

The nconf also needs ncurses packages.  HOSTLOADLIBES_nconf is set
to the libraries needed for nconf, but the cflags is not explicitly
set.  Actually, nconf relies on the check-lxdialog.sh for the proper
cflags:

HOST_EXTRACFLAGS += $(shell $(CONFIG_SHELL) $(check-lxdialog) -ccflags) \
                    -DLOCALE

The code above passes the ncurses flags to all objects, even for conf,
qconf, gconf.  Let's pass the ncurses flags only to mconf and nconf.

Currently, the presence of ncurses is not checked for nconf.  Let's
show a prompt like the mconf case.

According to Randy's report, the shell scripts still need to carry
the fallback code in case the pkg-config fails to find the ncurses
packages.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index c222745..a71596c 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -173,59 +173,49 @@
 	@echo  '  xenconfig       - Enable additional options for xen dom0 and guest kernel support'
 	@echo  '  tinyconfig	  - Configure the tiniest possible kernel'
 
-# lxdialog stuff
-check-lxdialog  := $(srctree)/$(src)/lxdialog/check-lxdialog.sh
-
-# Use recursively expanded variables so we do not call gcc unless
-# we really need to do so. (Do not call gcc as part of make mrproper)
-HOST_EXTRACFLAGS += $(shell $(CONFIG_SHELL) $(check-lxdialog) -ccflags) \
-                    -DLOCALE
-
 # ===========================================================================
 # Shared Makefile for the various kconfig executables:
 # conf:	  Used for defconfig, oldconfig and related targets
-# nconf:  Used for the nconfig target.
-#         Utilizes ncurses
-# mconf:  Used for the menuconfig target
-#         Utilizes the lxdialog package
 # object files used by all kconfig flavours
 
-lxdialog := lxdialog/checklist.o lxdialog/util.o lxdialog/inputbox.o
-lxdialog += lxdialog/textbox.o lxdialog/yesno.o lxdialog/menubox.o
-
 conf-objs	:= conf.o  zconf.tab.o
-mconf-objs     := mconf.o zconf.tab.o $(lxdialog)
-nconf-objs     := nconf.o zconf.tab.o nconf.gui.o
 kxgettext-objs	:= kxgettext.o zconf.tab.o
 
-hostprogs-y := conf nconf mconf kxgettext
+hostprogs-y := conf kxgettext
 
 targets		+= zconf.lex.c
 clean-files	+= gconf.glade.h
 clean-files     += config.pot linux.pot
 
-# Check that we have the required ncurses stuff installed for lxdialog (menuconfig)
-PHONY += $(obj)/dochecklxdialog
-$(addprefix $(obj)/, mconf.o $(lxdialog)): $(obj)/dochecklxdialog
-$(obj)/dochecklxdialog:
-	$(Q)$(CONFIG_SHELL) $(check-lxdialog) -check $(HOSTCC) $(HOST_EXTRACFLAGS) $(HOSTLOADLIBES_mconf)
-
-always := dochecklxdialog
-
 # Add environment specific flags
-HOST_EXTRACFLAGS += $(shell $(CONFIG_SHELL) $(srctree)/$(src)/check.sh $(HOSTCC) $(HOSTCFLAGS))
-HOST_EXTRACXXFLAGS += $(shell $(CONFIG_SHELL) $(srctree)/$(src)/check.sh $(HOSTCXX) $(HOSTCXXFLAGS))
-
+HOST_EXTRACFLAGS += $(shell $(CONFIG_SHELL) $(srctree)/$(src)/check.sh $(HOSTCC) $(HOSTCFLAGS)) \
+		    -DLOCALE
+HOST_EXTRACXXFLAGS += $(shell $(CONFIG_SHELL) $(srctree)/$(src)/check.sh $(HOSTCXX) $(HOSTCXXFLAGS)) \
+		    -DLOCALE
 # generated files seem to need this to find local include files
 HOSTCFLAGS_zconf.lex.o	:= -I$(src)
 HOSTCFLAGS_zconf.tab.o	:= -I$(src)
 
-HOSTLOADLIBES_mconf   = $(shell $(CONFIG_SHELL) $(check-lxdialog) -ldflags $(HOSTCC))
+# nconf: Used for the nconfig target based on ncurses
+hostprogs-y	+= nconf
+nconf-objs	:= nconf.o zconf.tab.o nconf.gui.o
 
-HOSTLOADLIBES_nconf	= $(shell \
-				pkg-config --libs menuw panelw ncursesw 2>/dev/null \
-				|| pkg-config --libs menu panel ncurses 2>/dev/null \
-				|| echo "-lmenu -lpanel -lncurses"  )
+HOSTLOADLIBES_nconf	= $(shell . $(obj)/.nconf-cfg && echo $$libs)
+HOSTCFLAGS_nconf.o	= $(shell . $(obj)/.nconf-cfg && echo $$cflags)
+HOSTCFLAGS_nconf.gui.o	= $(shell . $(obj)/.nconf-cfg && echo $$cflags)
+
+$(obj)/nconf.o: $(obj)/.nconf-cfg
+
+# mconf: Used for the menuconfig target based on lxdialog
+hostprogs-y	+= mconf
+lxdialog	:= checklist.o inputbox.o menubox.o textbox.o util.o yesno.o
+mconf-objs	:= mconf.o zconf.tab.o $(addprefix lxdialog/, $(lxdialog))
+
+HOSTLOADLIBES_mconf = $(shell . $(obj)/.mconf-cfg && echo $$libs)
+$(foreach f, mconf.o $(lxdialog), \
+  $(eval HOSTCFLAGS_$f = $$(shell . $(obj)/.mconf-cfg && echo $$$$cflags)))
+
+$(addprefix $(obj)/, mconf.o $(lxdialog)): $(obj)/.mconf-cfg
 
 # qconf: Used for the xconfig target based on Qt
 hostprogs-y	+= qconf