Emacs 25.2 is mostly a bug-fix release and I haven’t had any problems so I didn’t bother installing it as soon as it was released. Still, Irreal likes to be up-to-date on all things Emacs so I finally got around to compiling and installing it. Really, compiling it from source isn’t much harder than using homebrew or one of its siblings.
Here’s the recipe for compiling and installing it on macOS:
cd path-to-untared-source configure --with-ns CFLAGS="-g3 -O2 -I /usr/local/include/libxml2" make make install sudo mv nextstep/Emacs.app /Applications
I always mv my current Emacs to a backup version but that’s probably just irrational paranoia. The above recipe builds Emacs with EWW support. If you have additional needs, you may have to adjust the configure.
UPDATE : John Mastro commented that he thought specifying the CFLAGS variable to configure overroad the default value, which turns on some optimization. After some investigation, which you can read about in the comments, I discovered that that was indeed the case. I rebuilt Emacs with the new configure invocation shown above. If you followed the old recipe, you may want to do the same.