build: support for m68k (Motorola 68000's), by @cyan4973
build: improved AIX support, by @Helflym
build: improved meson unofficial build, by @eli-schwartz
+cli : custom memory limit when training dictionary (#2925), by @embg
cli : report advanced parameters information when compressing in very verbose mode (``-vv`), by @Svetlitski-FB
cli : limit --ultra levels to 21 in 32-bit mode, to reduce risks of OOM scenarios (#2885, @yoniko)