Compiling from source with --enable-ipv6

[Anand Buddhdev]

I'm trying to build BIRD from sources. If I build without any options,
then I end up with a binary called "bird" and its associated control
programs, "bird" and "birdcl". This build is only capable of IPv4. So
far I understand it.

If I configure with the option --enable-ipv6, and build it, I end up
with the binary "bird6", and the control programs, "birdc6" and "birdcl6".

My question is: is bird6 only able to handle IPv6, or will it also
handle IPv4?

If it will only handle IPv6, then I would need both bird and bird6. Is
there any way to get the build process to build both bird and bird6
without having to "make clean" and reconfigure?

Is there any reason why a single bird binary won't just handle both IPv4
and IPv6?

The documentation isn't clear about any of this, and could do with some
improvement.

Regards,

Anand