[lug] OT: Makefile oddity

[Michael J. Hammel]

Thus spoke D. Stimits
> Ok, I can later use ${SOMETHING}, even if it is just echo. But, I was
> coming up with problems of dual attempts to build targets in a project
> split into separate directories. So I ran with -d for debug mode. Turns
> out that:
> include Makefile.something
> 
> ...is doing the right thing, and after that, it is calling "include" a
> target! It then tries to figure out how to build Makefile.something,

This seems about right, and one of the reasons I eventually moved my
projects (many years preceeding auto-conf) to imake.  Imake will handle
this situation quite well, as it uses a preprocessor to manage the #includes.

I use included files in many places, many of which include variables that
are set using external scripts (GIMPINCS = `gimptool --cflags` for
example).

> Perhaps I need some sort of dummy rule that will force make to see
> target "include" as always up-to-date? I want to include separate files
> for subdirectory definitions, but I want it to only add definitions, I

You need to force make to preprocess the includes first, then process the
Makefile a second time, the way imake does with Imakefiles.  Not sure if
you can do that with make, but possibly if you integrate it with m4 or
something (not that I know much about m4).

> do not want it to end up doing multiple evaluations of everything under
> the mistaken assumption that "include Makefile.whatever" is a target and
> source file. Has anyone here seen this problem before or found a way to
> deal with it? 

imake - It's not just for X.  And there is a decent text on it from
O'Reilly:  Managing Portability with imake.

The easiest way to handle imake is to make use of the imake templates
delivered with a stock XFree86 installation and use the "xmkmf" script.
However, you can write your own templates and skip the X stuff altogether.

Note that learning imake is a lot less difficult than trying to learn
auto-conf if you already know Makefile formats.
-- 
Michael J. Hammel                               The Graphics Muse 
mjhammel at graphics-muse.org                      http://www.graphics-muse.com
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