Adding strlcpy and strlcat replacements to libradius

[Nicolas Baradakis]

> I think we may perhaps add an autoconf test to detect whether the
> system provides the srtlcpy and strlcat functions from OpenBSD.
> If they're not present, we'd compile a replacement in libradius.

Where should I put the prototypes of strlcpy and strlcat ?

I'm a little lost in the files in src/include. Sometimes replacement
functions are declared in libradius.h, sometimes in missing.h. There
are many things in missing.h not related to things in missing.c.

-- 
Nicolas Baradakis