gh-115765: Document and enforce Autoconf 2.72 requirement (#128502)

Author: erlend-aasland

Doc/using/configure.rst

@@ -29,7 +29,7 @@ Features and minimum versions required to build CPython:
 
 * Tcl/Tk 8.5.12 for the :mod:`tkinter` module.
 
-* Autoconf 2.71 and aclocal 1.16.5 are required to regenerate the
+* Autoconf 2.72 and aclocal 1.16.5 are required to regenerate the
   :file:`configure` script.
 
 .. versionchanged:: 3.1
@@ -58,6 +58,9 @@ Features and minimum versions required to build CPython:
 .. versionchanged:: 3.13
    Autoconf 2.71, aclocal 1.16.5 and SQLite 3.15.2 are now required.
 
+.. versionchanged:: next
+   Autoconf 2.72 is now required.
+
 See also :pep:`7` "Style Guide for C Code" and :pep:`11` "CPython platform
 support".
 

configure.ac

@@ -2,7 +2,7 @@ dnl ************************************************************
 dnl * Please run autoreconf -ivf -Werror to test your changes! *
 dnl ************************************************************
 dnl
-dnl Python's configure script requires autoconf 2.71, autoconf-archive,
+dnl Python's configure script requires autoconf 2.72, autoconf-archive,
 dnl aclocal 1.16, and pkg-config.
 dnl
 dnl It is recommended to use the Tools/build/regen-configure.sh shell script
@@ -12,7 +12,7 @@ dnl
 # Set VERSION so we only need to edit in one place (i.e., here)
 m4_define([PYTHON_VERSION], [3.14])
 
-AC_PREREQ([2.71])
+AC_PREREQ([2.72])
 
 AC_INIT([python],[PYTHON_VERSION],[https://github.com/python/cpython/issues/])