[petsc-dev] python2 vs python3 wrt configure

[Satish Balay]

http://lwn.net/Articles/571528/
https://fedoraproject.org/wiki/Changes/Python_3_as_Default
http://www.python.org/dev/peps/pep-0394/

>>>>>>

    * python2 will refer to some version of Python 2.x.

    * python3 will refer to some version of Python 3.x.

    * for the time being, all distributions should ensure that python
      refers to the same target as python2.

    * however, end users should be aware that python refers to python3
      on at least Arch Linux (that change is what prompted the
      creation of this PEP), so python should be used in the shebang
      line only for scripts that are source compatible with both
      Python 2 and 3.

    * in preparation for an eventual change in the default version of
      Python, Python 2 only scripts should either be updated to be
      source compatible with Python 3 or else to use python2 in the
      shebang line.

<<<<<<<<<<<

So configure using '#!/usr/bin/env python' should be fine for a while
- and at some point it can be switched to '#!/usr/bin/env python2' if
needed.

Satish