[ccan] [RFC] ccan: rename config file to ccan_config.h

[Rusty Russell]

"Emilio G. Cota" <cota at braap.org> writes:
> From: "Emilio G. Cota" <cota at braap.org>
>
> This avoids clashes with library users' code, who might
> have already a config.h header file.

But why would they want a separate one for CCAN?  That's just fraught
with danger.

For example, there's nothing wrong with your config.h including
ccan/ccan_config.h.

Cheers,
Rusty.