Which build system will do this the most 'naturally'?

Question

Instead of the flat structure my code currently has, I want to organize it into modules contained in sub-folders (and perhaps sub-sub folders if the modules get big enough).

Each module will have one or more translation units which will each produce a .o file. The final target would be to mash up all these object files into a static library (for now).

I am using plain 'make' and it is already complicated enough.
Is there a system in which the specified model comes naturally or with much less effort compared to writing makefiles by hand ? (If you are going to recommend cmake, I need some hints as I have already tried and could not come up with a good solution.)

Answer 1

Some paraphrased bits from my current project's makefile that may help you out with good old fashioned GNU make:

SOURCEDIR := dir1 dir2/subdir1 dir3 dir4 dir5/subdir1 dir6/subdir1
SOURCES := $(foreach srcdir,$(SOURCEDIR),$(wildcard $(srcdir)/*.c))
OBJECTS := $(patsubst %.c,build/%.o,$(SOURCES))
OBJDIRS := $(addprefix build/,$(SOURCEDIR))
MAKEDEPS := $(patsubst %.c,build/%.d,$(SOURCES))

all: example

$(OBJDIRS):
    -mkdir -p $@

build: $(OBJDIRS)

build/%.o : %.c | build
    cc -MMD -c -o $@ $<

example: $(OBJECTS)
    cc -o $@ $(OBJECTS)

-include $(MAKEDEPS)

In essence, it builds all of the source files found in the designated directories into object files located in subdirectories of the build directory in a hierarchy that parallels their source directory layout (important if multiple source files have the same name) and then links the results into an executable example.

As a bonus, dynamic dependency generation and inclusion via the MAKEDEPS variable and clang's -MMD flag.

Answer 2

It really depends upon your purposes: Build packages are generally intended for the audience rather than the performer. Often, they take into consideration the disparate environments into which people deploy. I played around with 'tup,' which seemed more a way of generating an executable as quickly as possible after an edit. 'Premake' seems to shoot at multiple platforms, but I found specifying compiler options no more enlightened than with Cmake.

It looks as though you've found a good Makefile tutor, so I'll leave my observations at that.