riscv-rt: include device in link.x

[romancardenas]

This follows the approach of cortex-m-rt.

Related to #238

[rmsyn]

I think as long as this is opt-in (as it is now), end users still have the flexibility of defining their own device.x.

Do we have any build tests that enable this feature?

LGTM

[romancardenas]

Will try to work on it. It is a bit painful, as we need to make files visible to the linker. Maybe a tests-riscv crate? We cannot use the tests crate as trybuild and cross-compiled projects don't get along very well.

[rmsyn]

Will try to work on it. It is a bit painful, as we need to make files visible to the linker. Maybe a tests-riscv crate? We cannot use the tests crate as trybuild and cross-compiled projects don't get along very well.

No worries, I wasn't aware it was such a pain. I think the automated tests would definitely be very useful, but their lack is not necessarily a blocker for this set of changes.

Whatever you want to do.

[romancardenas]

Ok! I will merge this, open a similar PR, and then work on a better test scenario so we can experiment with the new features.