[Users] parameter of route(n)

[Jerome Martin]

> > I second this.
> > Currently, I do use m4 macros
> same I did, not feeling a strong demand for something else to route's 
> parameter as I do m4 macros for many other values in the config.

Don't get me wrong, having text labels in routes would not be enough for
me to stop using m4, only not having to use it for THAT. :-)

>  I was 
> looking some time ago to embed m4 in openser, but couldn't get a C 
> library for that. Is anybody aware of any m4 C library?

Sorry, nope. I though that GNU m4 had a linkable C object compiled by
default, but I did not double check that.

However, one issue I see there is the debugging complexity this adds :
how do you know the line of a parse error ? You can know where it is
located in the m4-preprocessed version; but never in the original m4
config file. This is one of the issues I see with using m4.