Patch to require Python 3.4 or later to build glibc

[Gabriel F. T. Gomes]

On Fri, 12 Oct 2018, Joseph Myers wrote:
>
>	* configure.ac (PYTHON_PROG): Use AC_CHECK_PROG_VER.  Set
>	critic_missing for versions before 3.4.
>	* configure: Regenerated.
>	* manual/install.texi (Tools for Compilation): Document
>	requirement for Python to build glibc.
>	* INSTALL: Regenerated.
>	* benchtests/Makefile [PYTHON]: Make code unconditional.
>	* conform/Makefile [PYTHON]: Likewise.
>	* manual/Makefile [PYTHON]: Likewise.
>	* math/Makefile [PYTHON]: Likewise.

Looks good to me.  I have a question, though...  Did you intentionally
left the checks for PYTHON in the Rules file?

>+AC_CHECK_PROG_VER(PYTHON_PROG, python3 python, --version,
>+  [Python \([0-9][0-9.]*\)],
>+  [3.[4-9]*|3.[1-9][0-9]*|[4-9].*|[1-9][0-9]*],

OK.