   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.

   GNU `m4' was originally written by Rene Seindal, with subsequent
changes by Franc,ois Pinard and other volunteers on the Internet.  All
names and email addresses can be found in the file `THANKS' from the
GNU `m4' distribution.

   This is release 1.4.  It is now to be considered stable, future
releases are only meant to fix bugs, increase speed, or improve
documentation.  However...

   An experimental feature, which would improve `m4' usefulness, allows
for changing the syntax for what is a "word" in `m4'.  You should use:
     ./configure --enable-changeword

if you want this feature compiled in.  The current implementation slows
down `m4' considerably and is hardly acceptable.  So, it might go away,
do not count on it yet.

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