[tlbuild] expand_depth vs. sigsegv check

[Bruno Haible]

Nelson H. F. Beebe writes:
> Typically, on Unix, bad things happen when the stack is too small, and
> there is generally no way to catch a stack overflow from deep
> recursion: one just gets a segment violation and immediate
> termination

Well, there is a way to catch stack overflow: GNU libsigsegv.

But here, since TeX already has an expansion depth limit built-in,
use of GNU libsigsegv would be overkill - except on the very particular
system Karl is mentioning.

Bruno