Problem Creating Directories

[Bogdan]

Hello,

I have the following problem which boils down to directory creation, in case 
anyone can help me with it.

I have a project makefile which generates and includes makefiles for all of the 
project's modules. By generation, I really mean they are processed with m4. 
Before anyone says anything, yes, I am aware that I could be using GNU 
Autotools to solve my problem but I would still like to figure out what I am 
doing wrong. Here is the directory structure:

project - The project directory
project/makefiles - Here is where the makefiles are to be generated
project/src - Here is where the modules go
project/src/foo - Example module
project/src/bar - Example module

There are four files in this dummy project:

project/makefile - The main makefile which includes everything from the 
makefiles directory
project/src/project.m4 - Generate makefiles/project.mk to select modules
project/src/foo/foo.m4 - Generate makefiles/foo/foo.mk to build component foo
project/src/bar/bar.m4 - Generate makefiles/bar/bar.mk to build component bar

Here is what I expect to be generated:

project/makefiles/project.mk
project/makefiles/foo/foo.mk
project/makefiles/bar/bar.mk

Here is project/makefile:

SRC_DIR = src
MAKE_DIR = makefiles

$(MAKE_DIR)/%.mk: $(SRC_DIR)/%.m4 | $(MAKE_DIR)/$(MODULE); m4 $< $@
$(MAKE_DIR)/$(MODULE): ; mkdir -p $@

include $(MAKE_DIR)/project.mk

I know MODULE isn't defined at the point of the inclusion; that is because I 
want the macro to expand to the empty string such that the "makefiles" 
subdirectory can be created. This macro will be relevant later and should 
expand on usage.

Since this is just a dummy test project, there isn't actually any m4 processing 
being done so project.m4 and project.mk will end up looking identical. Here are 
the contents:

MODULE = foo
include $(MAKE_DIR)/$(MODULE)/foo.mk

MODULE = bar
include $(MAKE_DIR)/$(MODULE)/bar.mk

Nothing else happens because foo.m4 and bar.m4 are empty. There is no target; I 
only expect this to generate the makefiles mentioned above for me (after all, 
make can't know that there is no target until it's done generating and 
including all the makefiles).

Here's what's wrong:

$ make
makefile:7: makefiles/project.mk: No such file or directory
mkdir -p makefiles/
m4 src/project.m4 >makefiles/project.mk
makefiles/project.mk:2: makefiles/foo/foo.mk: No such file or directory
makefiles/project.mk:5: makefiles/bar/bar.mk: No such file or directory
m4 src/bar/bar.m4 >makefiles/bar/bar.mk
/bin/sh: 1: cannot create makefiles/bar/bar/.mk: Directory nonexistent
makefile:4: recipe for target 'makefiles/bar/bar.mk' failed
make: *** [makefiles/bar/bar.mk] Error 2

The "No such file or directory" lines don't bother me. They are there because I 
didn't silence the include directives; make should attempt to generate what's 
being included and restart. As you can see, generating project.mk causes the 
makefiles subdirectory to be created. Why doesn't this happen in the case of 
foo.mk and bar.mk as well?