gcc9 grew a new warning for unbounded allocas. Checking against some
bound is a way to quiet the warning. The bound I have inserted here is
copy and pasted from the kernel dtrace_dof_maxsize.
However both this check and the alloca remain a little gross. I am open
to input as to the right way or place to fix this. A few questions:
- Does any patch belong here, or do we go through an upstream?
- Would it be better just to disable the warning?
- Would it be better to convert the allocas in the file to dt_alloc? I think this is the right thing to do, I'm just wary of writing a bigger patch given that I don't know how dtrace is being maintained.