[PATCH] PR35457, provide system to backport autoconf 2.60+ bugfixes

[Ralf Wildenhues]

* Paolo Bonzini wrote on Fri, Apr 18, 2008 at 01:15:39PM CEST:
> Joseph S. Myers wrote:
>>
>> I don't see any likely reason to switch to a new version other than the 
>> latest (of autoconf and automake, I don't know about libtool).

Agreed.  Still, the additional version override information is very
helpful for porting.

Thanks for your checklist of things to look out for.

> Regarding libtool, it would be a good time to switch to the latest  
> stable release, or even to (yeah!) remove libtool from the GCC tree and  
> just tell developers to use 2.2.x.  However, we're not having bugs  
> reported on what we currently have, which is why I haven't yet tried to  
> do this.

I was going to propose this after 2.2.4, for at least one cross
compiling issue that has not been addressed in 2.2.2 yet.  If you think
it's better to do the switch early in the development cycle, to have
more time to iron out eventual issues, that's fine with me, too.  But I
do think GCC should just keep a copy in the tree, that makes for better
reproducability of bug reports.

Cheers,
Ralf