Re: Parallel configure

[Paul Eggert]

On 1/28/21 9:44 AM, Gavin Smith wrote:
> One big question is whether you are going to think of your
> configuration step as:
>
> * linear script with a parallel part in it (i.e. call make from shell), or
> * a parallel system with a linear part in it (i.e. call shell from make)

We need both.

If we're going to do this as an upward-compatible extension to Autoconf, 
one way to move forward is to think of the current 'configure' script as 
a top-level linear script, and your goal as a software developer will be 
to parallelize it as much as possible. Presumably you'd do that by 
invoking a new Autoconf macro; this macro would run 'make -j' (i.e., 
call make from shell) and each 'make' rule (running in parallel) would 
typically invoke the shell (i.e., call shell from make). This could even 
nest further, though I expect that'd be relatively rare. I assume we'd 
need variants of AC_REQUIRE that help us do dependencies better (I'm 
handwaving here...).

If we're going to do an incompatible replacement for Autoconf there are 
surely many other possibilities.