eliminate warnings from arlex.c

[Dr. Franz Fehringer]

> > I know this is not particularly helpful, but I think the right
> > approach here is to fix flex.  flex should be providing prototypes
> > for the functions which it provides.  Those functions declarations
> > are by and large only meaningful for flex, and they are at least
> > marginally vulnerable to breaking if a new version of flex ever
> > comes out.
> 
> Actually, it is particularly helpful ;-).  My system had flex 2.5.31
> installed, but 2.5.4 is more recent, so I installed that and the

No, 2.5.31 is (much) more recent.

Greetings

Franz Fehringer