RTI exit while saving the trace file

[ChadliaJerad]

This PR enables saving the trace file of the RTI, also after receiving a kill (Ctrl-C) signal.
This will help with debugging failing federated executions.

[edwardalee]

Some questions and suggestions. Thanks for fixing the printf format warnings too!

[erlingrj]

Nice addition to the RTI :)

[ChadliaJerad]

@edwardalee and @erlingrj, I still don't get why the tests are not passing.
Can you please double-check?

[edwardalee]

I have no idea why these tests are not passing. Looks like a socket connection was broken while downloading gradle? @petervdonovan : any ideas?

[edwardalee]

LGTM! I don't think the test failures have anything to do with these changes.

[ChadliaJerad]

BTW, lf-gedf-np and lf-gedf-np-ci tests succeed in #224, which already has updates merged from rti-exit-save-trace (into rti-refactoring branch).

[petervdonovan]

I have no idea why these tests are not passing. Looks like a socket connection was broken while downloading gradle? @petervdonovan : any ideas?

Three tests failed, all for different reasons:

• I agree that there was a network issue while downloading Gradle. This isn't really our fault, although I suppose we could look into caching like what Marten implemented for Windows in lingua-franca. EDIT: It looks like the C tests already benefit from Gradle daemon brought down to free locks in Windows CI lingua-franca#1694, so there is nothing more we can do.
• lf-gedf-np-ci tests are failing due to the bug that I pushed to master a few days ago. I expect the fix to be merged in the next couple of hours. (Fix bugs in name mangling lingua-franca#1816)
• I don't know why the lf-adaptive tests failed, but it looks like some kind of flaky test failure related to federated communication. There isn't a lot of information to go on:

Federate DistributedCMakeIncludeSeparateCompile in Federation ID 'f6dd8f3f58e226751a9650be2bdc2372fd558d9f8a5271d5'
    #### Launching the federate federate__f1.
    #### Launching the federate federate__b1.
    #### Bringing the RTI back to foreground so it can receive Control-C.
    RTI -i ${FEDERATION_ID} -n 2 -c init exchanges-per-interval 10
    Federate 0: ERROR: Read 0 bytes, but expected 1. errno=57
    Federate 0: FATAL ERROR: Failed to read response from RTI.

EDIT: Raised an issue: lf-lang/lingua-franca#1819

EDIT: The bottom line is that I agree with Edward that the test failures are probably unrelated to these changes.