add KOR_BASE variable in Makefile

Makefile

@@ -1,6 +1,9 @@
 # the repository might not have been checked out yet, so make this
 # able to fail:
--include koreader-base/Makefile.defs
+-include $(KOR_BASE)/Makefile.defs
+
+# koreader-base directory
+KOR_BASE=koreader-base
 
 # we want VERSION to carry the version of koreader, not koreader-base
 VERSION=$(shell git describe HEAD)
@@ -14,50 +17,49 @@ EMU_DIR=emu
 # files to copy from main directory
 LUA_FILES=reader.lua
 
-all: koreader-base/koreader-base koreader-base/extr
-
-koreader-base/koreader-base:
-	cd koreader-base && make koreader-base
+all: $(KOR_BASE)/koreader-base $(KOR_BASE)/extr
 
-koreader-base/extr:
-	cd koreader-base && make extr
+$(KOR_BASE)/koreader-base $(KOR_BASE)/extr:
+	make -C $(KOR_BASE) koreader-base extr
 
 fetchthirdparty:
 	git submodule init
 	git submodule update
-	cd koreader-base && make fetchthirdparty
+	make -C $(KOR_BASE) fetchthirdparty
 
 clean:
-	cd koreader-base && make clean
+	make -C $(KOR_BASE) clean
 
 cleanthirdparty:
-	cd koreader-base && make cleanthirdparty
+	make -C $(KOR_BASE) cleanthirdparty
 
 bootstrapemu:
 	test -d $(EMU_DIR) || mkdir $(EMU_DIR)
-	test -d $(EMU_DIR)/libs-emu || (cd $(EMU_DIR) && ln -s ../koreader-base/libs-emu ./)
-	test -d $(EMU_DIR)/fonts || (cd $(EMU_DIR) && ln -s ../koreader-base/fonts ./)
-	test -d $(EMU_DIR)/data || (cd $(EMU_DIR) && ln -s ../koreader-base/data ./)
+	test -d $(EMU_DIR)/libs-emu || (cd $(EMU_DIR) && ln -s ../$(KOR_BASE)/libs-emu ./)
+	test -d $(EMU_DIR)/fonts || (cd $(EMU_DIR) && ln -s ../$(KOR_BASE)/fonts ./)
+	test -d $(EMU_DIR)/data || (cd $(EMU_DIR) && ln -s ../$(KOR_BASE)/data ./)
 	test -d $(EMU_DIR)/frontend || (cd $(EMU_DIR) && ln -s ../frontend ./)
 	test -d $(EMU_DIR)/resources || (cd $(EMU_DIR) && ln -s ../resources ./)
-	test -e $(EMU_DIR)/koreader-base || (cd $(EMU_DIR) && ln -s ../koreader-base/koreader-base ./)
-	test -e $(EMU_DIR)/extr || (cd $(EMU_DIR) && ln -s ../koreader-base/extr ./)
+	test -e $(EMU_DIR)/koreader-base || (cd $(EMU_DIR) && ln -s ../$(KOR_BASE)/koreader-base ./)
+	test -e $(EMU_DIR)/extr || (cd $(EMU_DIR) && ln -s ../$(KOR_BASE)/extr ./)
 	test -e $(EMU_DIR)/reader.lua || (cd $(EMU_DIR) && ln -s ../reader.lua ./)
 
-customupdate: koreader-base/koreader-base koreader-base/extr
+customupdate: $(KOR_BASE)/koreader-base $(KOR_BASE)/extr
 	# ensure that the binaries were built for ARM
-	file koreader-base/koreader-base | grep ARM || exit 1
-	file koreader-base/extr | grep ARM || exit 1
+	file $(KOR_BASE)/koreader-base | grep ARM || exit 1
+	file $(KOR_BASE)/extr | grep ARM || exit 1
+	# remove old package and dir if any
 	rm -f koreader-$(VERSION).zip
 	rm -rf $(INSTALL_DIR)
+	# create new dir for package
 	mkdir -p $(INSTALL_DIR)/{history,screenshots,clipboard,libs}
-	cp -p README.md COPYING koreader-base/koreader-base koreader-base/extr kpdf.sh $(LUA_FILES) $(INSTALL_DIR)
+	cp -p README.md COPYING $(KOR_BASE)/{koreader-base,extr} kpdf.sh $(LUA_FILES) $(INSTALL_DIR)
 	$(STRIP) --strip-unneeded $(INSTALL_DIR)/koreader-base $(INSTALL_DIR)/extr
 	mkdir $(INSTALL_DIR)/data
-	cp -L koreader-base/$(DJVULIB) koreader-base/$(CRELIB) koreader-base/$(LUALIB) koreader-base/$(K2PDFOPTLIB) $(INSTALL_DIR)/libs
+	cp -L koreader-base/$(DJVULIB) $(KOR_BASE)/$(CRELIB) $(KOR_BASE)/$(LUALIB) $(KOR_BASE)/$(K2PDFOPTLIB) $(INSTALL_DIR)/libs
 	$(STRIP) --strip-unneeded $(INSTALL_DIR)/libs/*
-	cp -rpL koreader-base/data/*.css $(INSTALL_DIR)/data
-	cp -rpL koreader-base/fonts $(INSTALL_DIR)
+	cp -rpL $(KOR_BASE)/data/*.css $(INSTALL_DIR)/data
+	cp -rpL $(KOR_BASE)/fonts $(INSTALL_DIR)
 	rm $(INSTALL_DIR)/fonts/droid/DroidSansFallbackFull.ttf
 	echo $(VERSION) > git-rev
 	cp -r git-rev resources $(INSTALL_DIR)
@@ -65,4 +67,5 @@ customupdate: koreader-base/koreader-base koreader-base/extr
 	mkdir $(INSTALL_DIR)/fonts/host
 	zip -9 -r koreader-$(VERSION).zip $(INSTALL_DIR) launchpad/ extensions/
 	rm -rf $(INSTALL_DIR)
-	@echo "copy koreader-$(VERSION).zip to /mnt/us/customupdates and install with shift+shift+I"
+	# @TODO write a installation script in KUAL   (houqp)
+