Re: [PATCH] AC_CONFIG_MACRO_DIRS: improve tracing and add sanity checks

[Adrian Bunk]

On Mon, Nov 12, 2012 at 05:41:29PM -0500, Nick Bowler wrote:
> On 2012-11-12 15:19 -0700, Eric Blake wrote:
>...
> > But since we can't make it continue to work with the new
> > semantics of AC_CONFIG_MACRO_DIRS, the best we can do (and indeed, what
> > we DID do) is loudly flag incorrect usage as an error rather than
> > silently change semantics.
> 
> Sorry, I don't understand.  You seem to be claiming that the addition of
> AC_CONFIG_MACRO_DIRS (an entirely new macro, with documented behaviour)
> to Autoconf will somehow break the following pattern if we don't also
> change the definition of AC_CONFIG_MACRO_DIR?
> 
>   configure.ac:
>   AC_CONFIG_MACRO_DIR([foo])
> 
>   Makefile.am:
>   ACLOCAL_AMFLAGS = -I foo
> 
> What breaks?  How does it break?  Why will this not continue to work
> exactly as it has in the past if we do not keep AC_CONFIG_MACRO_DIR's
> definition exactly as it is right now, i.e.:
> 
>   AC_DEFUN([AC_CONFIG_MACRO_DIR], [])
>   
> ?
>...

The problem is not the addition of AC_CONFIG_MACRO_DIRS itself,
but in the whole picture:

In the future libtool will use the result of tracing 
AC_CONFIG_MACRO_DIR_TRACE instead of grep'ing configure.ac.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed