bug#24751: 26.0.50; Regex stack overflow not detected properly (gets "Variable binding depth exceeds max-specpdl-size")

[Eli Zaretskii]

One other comment: the value of 'extra' in emacs.c looks too small to
me.  If we want to safely allocate the failure stack off the run-time
C stack, we should make 'extra' large enough to cover a typical GC,
which can take as many as 30K stack frames.  So I'd enlarge 'extra' to
be something like 1500000.