Re: CHECK_STRUCTS/dmpstruct.h mechanism is broken.

[Paul Eggert]

Alan Mackenzie wrote:
> Is there anything particular about Autoconf that
> makes it difficult to parallelise, or is it just a case of nobody
> stepping up to do the work?

Autoconf does not keep track of dependencies, and attempting to add dependency 
tracking would require a significant internal redesign. A plausible approach 
would be to turn 'configure' into a front-end to a GNU makefile instead of being 
a sequential shell script. (Alternatively I suppose one could try to keep track 
of dependencies in the shell; good luck with that!) There would be significant 
changes to the Autoconf input language. Plus I expect there would be a new 
requirement for GNU Make, which would be a show-stopper for some projects. For 
compatibility we'd need to continue to support older sequential configure.ac 
files. I'm not saying it couldn't be done, only that it's a much bigger deal 
than simply moving Emacs away from Autoconf.

"Nobody stepping up to do the work" is also a factor, of course.