[Bug c++/68159] Demangler crash (GDB PR 19190)

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68159

--- Comment #12 from H.J. Lu <hjl.tools at gmail dot com> ---
Created attachment 39042
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39042&action=edit
A patch to avoid stack oveflow