GNU m4
   GNU `m4' is an implementation of the traditional UNIX macro
processor.  It is mostly SVR4 compatible, although it has some
extensions (for example, handling more than 9 positional parameters to
macros).  `m4' also has builtin functions for including files, running
shell commands, doing arithmetic, etc.  Autoconf needs GNU `m4' for
generating `configure' scripts, but not for running them.

Maintainer: The OpenBSD ports mailing-list <ports@openbsd.org>

WWW: https://www.gnu.org/software/m4/
