[Buildroot] autoconf caching

[Waldemar Brodkorb <wbx@openadk.org>]

Hi,
Dallas Clement wrote,

> Hi All - I have seen posts on this subject before.? It looks like things flamed
> out.
> 
> http://lists.gnu.org/archive/html/autoconf/2012-11/msg00022.html
> 
> I'm getting killed by autoconf.? My builds take 1.5 hours even with ccache
> turned on.? Most of the cores in my very impressive build machine are sitting
> on their !#@ while autoconf is running.? Most of my packages rely on autotools
> and it seems that most of the time spent is running configure scripts.
> 
> Can anyone offer some advice on how to speed things up with autoconf?? Or is it
> a lost cause?
> 
> Many thanks,

There was an interesting discussion about performance on the autoconf
mailinglist:
http://lists.gnu.org/archive/html/autoconf/2014-03/msg00030.html

OpenWrt uses CONFIG_SITE with some global architecture and libc
dependent files, see here:
https://dev.openwrt.org/browser/trunk/include/site

OpenEmbedded uses CONFIG_SITE, too:
http://cgit.openembedded.org/openembedded-core/tree/meta/site
They have a lot of package specific values added to their files.

May be the OpenWrt way with just a few global cached values would be
a benefit for buildroot performance? 

best regards
        Waldemar