While gcc was quite correct in its warning, all I needed was to
explicitly truncate the string. I don't remember why I didn't do that
back when I made the changes in 4f58429137, but it works now, and the
surrounding code does expect the string to be no more than 15 chars
long. This fixes yet another memory leak (but timedemo over multiple
runs still leaks like a sieve).
ef87baf339