diff --git a/Makefile b/Makefile
index 77feb2b..fdb2401 100644
--- a/Makefile
+++ b/Makefile
@@ -7,19 +7,24 @@ NEF = G		# Generator (shell functions and generator loop)
 NEF+= R		# Renderer  (awk script to convert to compliant HTML)
 NEF+= L		# Layout    (template script expanded by X)
 
-INPUT = I/*	# regular files
-INPUT+= I/.??*	# hidden files (for the footer)
+INPUT = $(wildcard I/*)	# regular files
+INPUT+= $(wildcard I/.??*)	# hidden files (for the footer)
 
-STATIC = S/*    # static files
+STATIC = $(wildcard S/*)    # static files
 
 OUTPUT =$(patsubst I/%,O/%,$(INPUT))
-OUTPUT+=$(patsubst S/%,O/S/%,$(INPUT))
+OUTPUT+=$(patsubst S/%,O/S/%,$(STATIC))
 
-.PHONY: all
+.PHONY: all clean
 all: $(OUTPUT)
+clean:
+	rm -rf O
 
-O/S/%: S/%
-	cp -r $< $@
+O:; mkdir -p O
+O/S: O;	mkdir -p O/S
+
+O/S/%: S/% O/S
+	cp $< $@
 
 O/%: I/% $(NEF)
 	$(BUILD) $<
diff --git a/nef b/nef
index dc4b5b5..a4d6574 160000
--- a/nef
+++ b/nef
@@ -1 +1 @@
-Subproject commit dc4b5b5a0703b6aac2d310bcdd2957e4dc7efe0c
+Subproject commit a4d6574ffb752b31093c30fe3c7d68710e9e1b50