Re: configure speedup proposal: add --assume-c99 and --assume-posix2008 flags

[Paul Eggert]

Rhys Ulerich wrote:

> Is there some reason configure caches are unsuitable to
> gain speedup there?

I regularly build with experimental versions in which the 'configure' 
tests themselves differ from run to run, and where configure caches 
would give me incorrect results.  So I never use caches.

I have to wait for an unreasonably long period of time whenever I change 
anything that requires reconfiguration, and this happens quite 
frequently to me (often several times per day).

> one just 35 seconds long.

It's a 35-second wait in an edit-build-run cycle, and that's wayy too 
long.  I typically give up and work on something else for a while.  The 
mental context-switching overhead is extremely annoying.

I would greatly appreciate it if 'configure' ran faster.