Autoconf 2.59d (released in 2006) [1] started promoting several macros
as not relevant for newer systems anymore, including the `AC_FUNC_MEMCMP`.
On some old systems such as SunOS 4.1.3 (EOL in 2003) and NeXT x86
OpenStep (discontinued) the `memcmp` function wasn't present or it
didn't work properly. [2]
On current systems including at least Solaris 10+ this check is not
relevant anymore.
projects / onig / commit