update makefiles

Makefile

@@ -1,13 +1,14 @@
-BUILDDIR = ./build
-projs = grs info blog apps os
+BUILDDIR?=./build
+PROJS?=grs info blog apps os
 copyfiles =  index.ls mimes.json
 main:  copy
-	for f in $(projs); do  make -C  "$${f}" ; done
+	for f in $(PROJS); do  BUILDDIR=$(BUILDDIR)/"$${f}" make -C  "$${f}" ; done
 
 copy:
 	cp -rf $(copyfiles) $(BUILDDIR)
 	cp -r silk $(BUILDDIR)
 
 clean:
-	-for f in $(projs); do rm -r $(BUILDDIR)/"$${f}"; done
+	-for f in $(PROJS); do rm -r $(BUILDDIR)/"$${f}"; done
+	-for f in $(copyfiles); do rm -r $(BUILDDIR)/"$${f}"; done
 	-rm -r $(BUILDDIR)/silk