Iterating directories and conditions in makefiles - makefile

Question

I have a repository structure where dependencies can either be svn:external'd either in this repository or in a super-repository which has svn:external'd this one. The externals are only one level deep and so if my repo is externalized by a super-repository, then I need to be able to detect where to find the dependency at a higher level, and copy over all relevant data. If the dependency is indeed found in my own repository, then I need to build it.
I am having problems creating my makefile recipe to do this. Here is what I have so far:
DEPENDENCIES = dep1 dep2
ROOTDIR = .
deps :
for dep in $(DEPENDENCIES); do \
if [ -e $(ROOTDIR)/ext/$$dep ]; then \
depdir = $(ROOTDIR)/ext/$$dep; \
$(MAKE) -C $depdir; \
elif [ -e $(ROOTDIR)/../$$dep ]; then \
depdir = $(ROOTDIR)/../$$dep; \
else \
$(error Could not find dependency: $$dep) \
fi \
cp $$depdir/bin/* $(ROOTDIR)/bin; \
cp $$depdir/lib/* $(ROOTDIR)/lib; \
cp $$depdir/inc/$$dep $(ROOTDIR)/inc/$$dep; \
done
First problem is the $(error ) line. I'd like to be able to throw an error, but this is clearly not subjected to the bash condition statements. This is the output:
$ make deps
makefile:108: *** Could not find dependency: $dep. Stop.
If I comment out that else statement, then I'm still having troubles
$ make deps
for dep in dep1 dep2; do \
if [ -e ./ext/$dep ]; then \
/bin/sh: -c: line 2: syntax error: unexpected end of file
make: *** [makefile:106: deps] Error 1
Could someone provide some hints regarding how to accomplish this? I'm running GNU make in both cygwin and linux environments.
Edit: I'd really prefer to keep this as close to make as possible (and as little shell stuff). I think I've gotten a little closer, but still need to repeat this for each item in $(DEPENDENCIES).
DEPENDENCIES = foo bar
ROOTDIR = .
EXTDIR = $(ROOTDIR)/ext
BINDIR = $(ROOTDIR)/bin
INCDIR = $(ROOTDIR)/inc
# Need a foreach DEP in $(DEPENDENCIES) here
ifneq("$(wildcard $(EXTDIR)/$(DEP))","")
DEPDIR = $(EXTDIR)/$(DEP)
BUILDDEP = $(MAKE) -C $(DEPDIR)/build
else ifneq("$(wildcard $(ROOTDIR)../$(dep))", "")
DEPDIR = $(ROOTDIR)/../$(dep)
else
$(error Could not find dependency: $(DEP))
endif
$(DEPDIR) :
$(BUILDDEP)
cp $(DEPDIR)/bin/* $(BINDIR)
cp $(DEPDIR)/inc/$(DEP)/* $(INCDIR)/$(DEP)
Edit2:
I think I'm getting closer. The following looks more like what I want, but it still have problems:
1) I don't know how to call each recipe
2) It doesn't give an error if it doesn't find all dependencies
3) It doesn't let me dictate the build order
4) It doesn't let me filter to use only folders listed in dependencies (it does all folders)
ifneq "$(wildcard $(EXTDIR)/%/build)" ""
$(EXTDIR)/%:
$(MAKE) -C $(EXTDIR)/%/build
cp $(EXTDIR)/%/bin/* $(BINDIR)
cp $(EXTDIR)/%/int/*.a $(INTDIR)
cp $(EXTDIR)/%/inc/%/* $(INCDIR)/%
endif
ifneq "$(wildcard $(ROOTDIR)/../%/build)" ""
DEPDIR = $(ROOTDIR)/..
$(DEPDIR)/%:
cp $(DEPDIR)/%/bin/* $(BINDIR)
cp $(DEPDIR)/%/int/*.a $(INTDIR)
cp $(DEPDIR)/%/inc/%/* $(INCDIR)/%
endif
Edit3
After being told I was trying to solve too many problems at once, I've reduced it to this:
DEPENDENCIES = dep1 dep2 dep3
for each DEP in $(DEPENDENCIES)
$(DEP) :
$(MAKE) -C ../ext/$(DEP)
How can I create a recipe ($(DEP) ) for each item in $(DEPENDENCIES)?

Answer 1

Solved. This solves the problem above:
DEPENDENCIES = dep1 dep2 dep3
$(DEPENDENCIES) :
$(MAKE) -C ../ext/$#
The answer is very simple. I wish I knew enough about this stuff to ask a more legible question.