Public configuration headers

[mfox at cpsc dot ucalgary dot ca (Mark Fox)]

Greetings:

	Please pardon my ignorance, but I've recently run into the
problem of generating public configuration headers.  (Well, that's
what I'm calling them.)

	Basically, I'm defining a public configuration header as
something similar to 'config.h' except that it can be #included into a
user's code.  An example of what I'm talking about is something like
'glibconfig.h' or 'stl_config.h'.  These files contain macros that
affect the interface defined in the headers that a user #includes to
use the library.

	I've looked at how 'glibconfig.h' is generated and it's pretty
gross.  It's generated at configuration time rather than at build
time.  A lot of the hairyness involved is in trying to figure out just
when 'glibconfig.h' has to be rebuilt.

	What is needed is a way to generate a 'project_config.h'?  It
would contain the macros like 'PROJECT_HAVE_FLOAT_H' rather than just
'HAVE_FLOAT_H'.

	Does something like this already exist?  Is there an accepted
way of generating this sort of file?  (If not, a modified AC_DEFINE
seems appropriate.)
-- 

				Mark A. Fox
				mfox@cpsc.ucalgary.ca

	"All generalizations are false." - Anonymous