Re: [PATCH 07/12] use a shell function for AC_CHECK_HEADER

[Ralf Wildenhues]

* Paolo Bonzini wrote on Mon, Oct 27, 2008 at 10:35:19AM CET:
> Let's go again.  I retimed the effect of upgrading from 2.61 to after
> the whole series of patches, and I get a 45-55% reduction in autoconf
> execution time (approx. 20% are already there in 2.63) and 30-35%
> reduction in configure script size.  In other words, with the latest
> patches the complexity of m4sh processing is lowered, and the speedup
> is more consistent with the decrease in output size.

Out of curiosity, how much of the speedup is attributable to
improvements in m4 (or did you use the same version throughout)
and to the changes between 2.61 and 2.63?

> 2008-10-27  Paolo Bonzini  <address@hidden>
> 
>         * lib/autoconf/headers.m4 (_AC_CHECK_HEADER_OLD,
>         _AC_CHECK_HEADER_NEW): Use a shell function.

Please list all changed macros in the ChangeLog entry, even internal
ones, thanks.

It looks to me like overall, the shell function changes will make user
code even more reliant on correct M4 quotation than before.  I think
this deserves mention in the NEWS file, to give users a hint where to
start looking for issues.

Thanks,
Ralf