This is for Emacs. Currently, it provides a no-effect stub
on all platforms where it does not already work.
It already works on glibc-based systems, and on Solaris 11.
* lib/execinfo.c, lib/execinfo.in.h, m4/execinfo.m4, modules/execinfo:
New files.
* doc/glibc-headers/execinfo.texi (execinfo.h):
* MODULES.html.sh (Misc): Document it.
4ee642f60d