Re: Detecting (g)m4

[Eric Blake]

Akim Demaille <akim <at> lrde.epita.fr> writes:

> > Maybe not quite a bug, and maybe not your fault, but configure
> > apparently picks the first program called "gm4" in my path, >not<
> > the first appropriate m4 or gm4.
> 
> You are right, of course.  But it's more efforts to look for the  
> "best" m4 around, so improvements, unless contributed by some devoted  
> user (read my mind ;), are unlikely to be made soon.  Especially  

</me puts on ESP hat> Are you talking to me?

> because I see no existing Autoconf macro to address this issue.  Maybe  
> Autoconf itself has one (after all it is probably the most demanding  
> M4 application).

Which version of bison?  

I can confirm that the latest released version, bison 2.4, used m4/m4.m4 dating 
from 2000, which does indeed have severe limitations at detecting a good m4 
version.  You can work around them by calling './configure 
M4=/path/to/your/preferred/m4'.

Meanwhile, the latest git version uses serial 5 of autoconf's m4/m4.m4, which 
does a MUCH better job at picking m4 1.4.5 or newer, regardless of spelling.  
Autoconf itself has moved on to serial 6 (which now checks for the m4 -g flag 
added in m4 1.4.12 or newer), so maybe it's time to do another submodule update 
to pick that up.

-- 
Eric Blake