Side effect of change for Python 3.11 in configure.

[Blady-Com]

Configure was adapt to Python 3.11 in this change:

  am_cv_python_version=`$PYTHON -c "import sys; sys.stdout.write(sys.version.split(' ')[0])"`

Unfortunately, I got an error:

checking for python3.11.7... no
configure: error: Cannot find python3.11.7 in your system path

The explanation is that there is no executable python3.11.7 but only python3 and python3.11.

I had proposed this change to get only major and minor Python version:

am_cv_python_version=`$PYTHON -c "import sys,re; sys.stdout.write(re.findall(r'(\d+\.\d+)\.', sys.version)[0])"`

Then all is correct:
checking for python3.11... /Users/me/xnadalib-2024/bin/python3.11