Browsing the forum has paid off! This thread: Had to modify tasks.json to debug (?) described a similar problem. I tried the “magic sauce” - commenting out the “depends on” in the tasks.json for my original program, and voila! I’m able to debug. I am still seeing some “off by one” behavior, the debugger is pausing on a break statement rather than the line above it where I set a breakpoint (perhaps the same problem as the second example I posted, which was not improved by commenting out the “depends on”), but at least I can limp along now.
I would still like some help with getting printf running, if anybody reads this.