Removing support for Emacs unexec from Glibc
The Emacs editor requires a lot of Lisp code and program state before it can start doing its job. That led Emacs developers to add the "unexec" feature to quickly load all of that at startup, but unexec has always been something of a hack. It employs a fairly ugly (and intrusive) mechanism to do its job. Some non-standard extensions to the GNU C library (Glibc) are required, so a plan to eventually eliminate those extensions was met with some dismay in the Emacs community.