mage:recursive make::Frosty the Snowman:volcanic eruptions

In other words, recursive makefiles are totally avoided, for good reason.
Instead this project uses a single top-level makefile combined with module.mk
files and autogenerated .d dependency files.  Search for "recursive make
considered harmful" for an informative paper on why recusive makefiles are the
devil.

The top-level makefile includes module.mk files from each subproject in order to
develop a list of every source file and everything each of them needs.  In
practice I find this much, much cleaner than recursion--it is rather ugly to
type make and wait for an hour while it goes through directory after directory
of "Nothing to make for 'all'."  Here it knows this right away. ;^)

To modify an existing subproject's makefile, edit its module.mk.  It's
surprisingly simple.  Just don't forget to prefix every SRC entry with the
module's directory (e.g. libeast/object.cc).  The top-level makefile
figgers out what -I's are needed and so on and so forth.

To add a subproject (module?), create a new directory somewheres, add that
directory's name to the top-level Makefile's MODULES entry, and create a
module.mk in the directory.  Use the existing module.mk's as templates.  And
don't forget to prefix the source files!

Support this system.  I recommend emulating it in your own projects and/or
suggesting it to maintainers of existing projects either already using recursive
makefiles or about to start using them.  Feel free to reuse my wonderful
depend.sh script which can make a nice dependency list for your source files.
If you extend it to work with more than just .cc C++ source, send improvements
my way.  Or if you improve the makefile system in general, mail me about that
too.

And good luck.