Insert dependency in parallel makefile - makefile

Question

I'm trying to add an extra dependency to a rule in a parallel makefile. I might have found a way, but I'm in doubt. (I haven't written the original makefile and I'm not an expert in make.)
The original makefile looks like this:
VER = busybox-1.16.2
URL = http://busybox.net/downloads/$(VER).tar.bz2
export KBUILD_OUTPUT = $(ROOTDIR)/user/busybox/build-$(VER)
all: build-$(VER)/.config depmod.pl
$(MAKE) -C build-$(VER)
build-$(VER)/.config: $(ROOTDIR)/config/.config
mkdir -p build-$(VER)
sed -n \
-e '/_CROSS_COMPILER_PREFIX=/s:=.*:="$(CROSS_COMPILE)":' \
-e '/CONFIG_USER_BUSYBOX_/s:CONFIG_USER_BUSYBOX_:CONFIG_:p' \
$< > $#.uclinux-dist.new
set -e ; \
if [ ! -e $# ] || ! cmp -s $#.uclinux-dist.new $#.uclinux-dist.old ; then \
cp $#.uclinux-dist.new $#.uclinux-dist.old ; \
cp $#.uclinux-dist.old $# ; \
yes "" | $(MAKE) -C $(VER) oldconfig ; \
fi
depmod.pl: $(VER)/examples/depmod.pl
ln -sf $< $#
I want to add a 'download' rule to the make.
$(VER)/: $(VER).tar.bz2
tar -jxvf $(VER).tar.bz2
touch $#
$(VER).tar.bz2:
wget $(URL)
touch $#
This rule must be executed before anything else. The parallel build prevent constructs like
all: |$(VER)/ build-$(VER)/.config depmod.pl
(This works in single threaded builds.)
My solution so far is this:
VER = busybox-1.18.5
URL = http://busybox.net/downloads/$(VER).tar.bz2
export KBUILD_OUTPUT = $(ROOTDIR)/user/busybox/build-$(VER)
all: build-$(VER)/.config depmod.pl
$(MAKE) -C build-$(VER)
$(VER)/: $(VER).tar.bz2
tar -jxvf $(VER).tar.bz2
touch $#
$(VER).tar.bz2:
wget $(URL)
touch $#
build-$(VER)/.config: $(ROOTDIR)/config/.config | $(VER)/
mkdir -p build-$(VER)
sed -n \
-e '/_CROSS_COMPILER_PREFIX=/s:=.*:="$(CROSS_COMPILE)":' \
-e '/CONFIG_USER_BUSYBOX_/s:CONFIG_USER_BUSYBOX_:CONFIG_:p' \
$< > $#.uclinux-dist.new
set -e ; \
if [ ! -e $# ] || ! cmp -s $#.uclinux-dist.new $#.uclinux-dist.old ; then \
cp $#.uclinux-dist.new $#.uclinux-dist.old ; \
cp $#.uclinux-dist.old $# ; \
yes "" | $(MAKE) -C $(VER) oldconfig ; \
fi
depmod.pl: $(VER)/examples/depmod.pl
ln -sf $< $#
$(VER)/examples/depmod.pl: | $(VER)/
Problem is, I don't really know what kind of magic the depmod.pl rule is. Is it executed correctly, now that I've added an explicit empty rule?

Answer 1

I'd hate to answer my own question, but I think I've found the answer.
The dependency of the depmod.pl rule is not real/relevant in the original script.
The code:
depmod.pl: $(VER)/examples/depmod.pl
ln -sf $< $#
Ought to be written:
depmod.pl:
ln -sf $(VER)/examples/depmod.pl $#
So my extra empty rule makes no difference. In the new script, the dependency almost makes sence though.