Add RPi pico support for v0.7

[erlingrj]

The RPi pico support needs updates to support v0.7. In this PR I make a few minor changes needed. I have not setup the pico toolchain locally so haven't tested it. See: #2282 Maybe @sberkun can follow up on it?

Would be great with a simple CI test that at least builds a hello world to avoid this in the future. Do you have any estimate of how hard that would be Samuel?

[sberkun]

Sorry for the delay! Following some recent changes (splitting the runtime into many CMake modules), the libraries need to be added to lf-low-level-platform-api as well as reactor-c. lf-lang/reactor-c#344 addresses lf-low-level-platform-api and this PR (or #2178) addresses reactor-c.

Setting up a compilation test should be doable, the main steps are:

• install GCC cross compiler (see raspberrypi documentation)
• clone the sdk
• set PICO_SDK_PATH environment variable
• compile (but not run) a hello-world test

I'm not familiar with how the automated tests are set up, but I imagine this could be accomplished by copying the Ubuntu tests and adding a few lines.

[edwardalee]

Looks like this change is also included in #2178, so I think this can be safely be closed.

[lhstrh]

Looks like this change is also included in #2178, so I think this can be safely be closed.

@sberkun, could you confirm this?

[lhstrh]

Given the lack of response I'm assuming it's safe to close this.