Missing return warnings for GCC for switch statements

[jjwilke]

Several switch statements do not provide a trailing return or default case statement, leading GCC to spew complaints about missing return statements in memOp.h, nicEvents.h, and shmemapi.h

[hughes-c]

@jjwilke Should this go into 9.1?

[jwilso]

@jjwilke @hughes-c Was this ever addressed? I will leave it open if so.

[hughes-c]

@jwilso Not that I'm aware of.

[nmhamster]

@allevin / @jjwilke - do we have a list of these we can knock out for the release?

[allevin]

@jjwilke do you know what version of the gcc compiler was throwing the complaints?
I will try to do a warnings scrub next week.

[allevin]

@jjwilke @nmhamster I cannot reproduce these build warnings. I tried GCC 4.8 and GCC 6.1... The issue was submitted in 2019, and may have been cleaned up since. I recommend closing.