Hi,

I attach a patch that adds support for compressing buffers using
zlib. It is a minor extension to the file src/decompress.c but it may be
useful because of two reasons (i) in Windows, Emasc is shipped without
g[un]zip.exe, (ii) the whole process of compression takes about 20 times
less time than calling gzip.

(benchmark 1
  '(mapc 'simple-zlib-compress
      (directory-files  "~/emacs-build/git/emacs-27/lisp/" t ".*\\.el")))
;; => Elapsed time: 2.602588s (0.014894s in 1 GCs)

(benchmark 1
  '(mapc 'simple-gzip-compress
       (directory-files  "~/emacs-build/git/emacs-27/lisp/" t ".*\\.el")))
;; => Elapsed time: 61.986128s (0.039815s in 3 GCs)

I attach a patch that was produced against emacs-27 but also seems to
work against emacs-28 (at least the decompress.c part, I am unsure about
how NEWS should be edited).

I also attach a lisp file that test and benchmark the
compression/decompression using Emacs' lisp sources.

Best

Juanjo

-- 
Juan José García Ripoll
http://juanjose.garciaripoll.com
http://quinfog.hbar.es