Re: [PATCH] build: speed up configure for releases

[Jim Meyering]

Eric Blake wrote:

> At this point, we're pretty good about picking up gnulib dependencies
> without having to be warned about them.  The time spent in configure
> to check for declarations is pretty expensive, and really only needs
> to be done by a maintainer every once in a while, rather than by
> every downstream client on every configure run.
>
> * configure.ac (gl_ASSERT_NO_GNULIB_POSIXCHECK): Comment out,
> with a note why.
> ---
>
> I've been camping on this one for a long time; I guess it would be
> even more impressive if I compared benchmark numbers of the timing
> difference between using this patch and omitting it.

I timed it.

Before the change, running "env time --f=%e ./configure" (best of 3) gave this:
(using ccache and an ext4/SSD)

  52.89

After that change:

  46.31

i.e., saving over 6 seconds (more than 10%).