GNU M4 1.4.18 has been released. This release is a minor update, but
recommended for all users. The bulk of the changes have been to
portability fixes inherited from gnulib, since it has been more than
three years since the last release.
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 built-in functions for including files,
running shell commands, doing arithmetic, etc. Autoconf needs GNU
'm4' for generating 'configure' scripts, but not for running them.
[*] Use a .sig file to verify that the corresponding file (without the
.sig suffix) is intact. First, be sure to download both the .sig file
and the corresponding tarball. Then, run a command like this:
gpg --verify m4-1.4.18.tar.gz.sig
If that command fails because you don't have the required public key,
then run this command to import it: