README Build from Source: m4 (step 5) is needed to run make configure (step 3) #33553
Description
In the current README (https://gitlab.com/sagemath/sage/-/blob/develop/README.md), in the Instructions to Build from Source section, it says at step 3 to:
3. [Git] If you cloned the Sage repository using git, bootstrap the
source tree using:
$ make configure
On a bare debian linux version, the above fails becaue of the absence of m4.
The installation of m4 is suggested only at step 5:
5. [Linux, Cygwin] Install the required minimal build prerequisites.
Compilers: gcc, gfortran, g++ (a recent enough matching
set of these three will avoid building Sage-specific compilers).
See the Installation Manual for a discussion of suitable compilers.
Build tools: GNU make, GNU m4, perl (including
ExtUtils::MakeMaker), ranlib, git, tar, bc.
Python 3.4 or later, or Python 2.7, a full installation including
urllib; but ideally version 3.7.x, 3.8.x, or 3.9.x, which will
avoid having to build Sage's own copy of Python 3.
Component: documentation
Author: Matthias Koeppe
Branch/Commit: f1af3cb
Reviewer: Sébastien Labbé
Issue created by migration from https://trac.sagemath.org/ticket/33553