scripts/config: Add qconf target to Makefile

qconf is kconfig UI utilizing QT toolkit. This makes it possible to use
graphical interface interaction to configure LEDE build target.

This commit adds qconf target to ./script/config/Makefile to be used by
toplevel ``make xconfig`` later.

Signed-off-by: Alif M. Ahmad <alive4ever@live.com>

scripts/config/Makefile

@@ -7,6 +7,8 @@
 # conf:	  Used for defconfig, oldconfig and related targets
 # mconf:  Used for the mconfig target.
 #         Utilizes the lxdialog package
+# qconf:  Used for the xconfig target
+#         Based on Qt which needs to be installed to compile it
 # object files used by all kconfig flavours
 
 
@@ -18,19 +20,33 @@ check_lxdialog = $(shell $(SHELL) $(CURDIR)/lxdialog/check-lxdialog.sh -$(1))
 export CFLAGS += -DKBUILD_NO_NLS -I. $(call check_lxdialog,ccflags)
 export CXXFLAGS += -DKBUILD_NO_NLS
 
+DISTRO-PKG-CONFIG := $(shell which -a pkg-config | grep -E '\/usr' | head -n 1)
+
 conf-objs	:= conf.o zconf.tab.o
 mconf-objs	:= mconf.o zconf.tab.o
+qconf-cxxobjs	:= qconf.o
+qconf-objs	:= zconf.tab.o
+
 lxdialog-objs := \
 	lxdialog/checklist.o lxdialog/util.o lxdialog/inputbox.o \
 	lxdialog/textbox.o lxdialog/yesno.o lxdialog/menubox.o
 
 clean-files	:= zconf.tab.c lex.zconf.c zconf.hash.c
+# Remove qconf junk files
+clean-files	+= $(qconf-cxxobjs) qconf.moc .tmp_qtcheck
 
 all: conf mconf
 
 conf: $(conf-objs)
 mconf: $(mconf-objs) $(lxdialog-objs)
 	$(CC) -o $@ $^ $(call check_lxdialog,ldflags $(CC))
+qconf: $(qconf-cxxobjs) $(qconf-objs)
+ifneq ($(DISTRO-PKG-CONFIG),)
+	$(CXX) $(HOSTLOADLIBES_qconf) -o $@ $^
+else
+	echo "You don't have 'pkg-config' installed. Cannot continue"
+	echo "For now, you may use 'make menuconfig' instead of 'make xconfig'"
+endif
 
 clean:
 	rm -f *.o lxdialog/*.o $(clean-files) conf mconf
@@ -51,3 +67,43 @@ zconf.hash.c: zconf.gperf
 
 %.hash.c: %.gperf
 	cp $@_shipped $@ || gperf < $< > $@
+
+ifeq ($(MAKECMDGOALS),qconf)
+qconf.o: .tmp_qtcheck
+.tmp_qtcheck: Makefile
+-include .tmp_qtcheck
+
+# Qt needs some extra effort...
+.tmp_qtcheck:
+	@set -e; echo "  CHECK   qt"; \
+	if $(DISTRO-PKG-CONFIG) --exists Qt5Core; then \
+	    cflags="-std=c++11 -fPIC `$(DISTRO-PKG-CONFIG) --cflags Qt5Core Qt5Gui Qt5Widgets`"; \
+	    libs=`$(DISTRO-PKG-CONFIG) --libs Qt5Core Qt5Gui Qt5Widgets`; \
+	    moc=`$(DISTRO-PKG-CONFIG) --variable=host_bins Qt5Core`/moc; \
+	elif $(DISTRO-PKG-CONFIG) --exists QtCore; then \
+	    cflags=`$(DISTRO-PKG-CONFIG) --cflags QtCore QtGui`; \
+	    libs=`$(DISTRO-PKG-CONFIG) --libs QtCore QtGui`; \
+	    moc=`$(DISTRO-PKG-CONFIG) --variable=moc_location QtCore`; \
+	else \
+	    echo >&2 "*"; \
+	    echo >&2 "* Could not find Qt via $(DISTRO-PKG-CONFIG)."; \
+	    echo >&2 "* Please install either Qt 4.8 or 5.x. and make sure it's in PKG_CONFIG_PATH"; \
+	    echo >&2 "*"; \
+	    exit 1; \
+	fi; \
+	echo "KC_QT_CFLAGS=$$cflags" > $@; \
+	echo "KC_QT_LIBS=$$libs" >> $@; \
+	echo "KC_QT_MOC=$$moc" >> $@
+endif
+
+#Define compiler flags to build qconf
+HOSTLOADLIBES_qconf	= $(KC_QT_LIBS)
+HOSTCXXFLAGS_qconf.o	= $(KC_QT_CFLAGS)
+
+qconf.o: qconf.moc
+qconf.o: CXXFLAGS+=$(HOSTCXXFLAGS_qconf.o)
+
+moc = $(KC_QT_MOC) -i $< -o $@
+
+%.moc: %.h .tmp_qtcheck
+	$(call moc)