"I don’t expect them to be a full fledged C programmer, but I think it’s important to know how to build software. The candidates that have demonstrated these skills have also been more proficient in debugging, tracing system calls, and identifying performance problems ahead of time."I think the same is true of testers.
If you are a tester who has never used a compiler (or even if it's been a while), I have an exercise for you to do the next time you need inspiration for a new test.
Find your local build person, or a sympathetic developer, and have them send you the compiler log(s) from building your particular application. Do text string searches in the log files for the terms "warning" and "error". Unless you are working in an extremely mature organization, I'll bet you find some warnings and errors from the compiler.
Those errors and warnings point to places where bugs are very likely to live.