eo - callstack. realloc is a bad idea. use mmap and keep addr fixed

eo - callstack. realloc is a bad idea. use mmap and keep addr fixed

this fixes and eo2 problem where when callstack grows (or shrinks)
and realloc nas to relocate memory, the frame ptrs like fptr become
invalid and all sorts of hell ensues.

this uses mmap so blowing the stack will segv, not scribble over
memory, also its separated from malloc heap, and now big enough to not
need to size ... ever (1024 entries).