[master] also try to detect python3.2 executable

This is the executable name as installed on Debian with its
python3.2 package.

Python 3.2 appears to work and some have been using it for months.

configure.ac

@@ -120,7 +120,7 @@ AM_CONDITIONAL(SET_ENV_LIBRARY_PATH, test $SET_ENV_LIBRARY_PATH = yes)
 AC_SUBST(SET_ENV_LIBRARY_PATH)
 AC_SUBST(ENV_LIBRARY_PATH)
 
-m4_define([_AM_PYTHON_INTERPRETER_LIST], [python python3 python3.1])
+m4_define([_AM_PYTHON_INTERPRETER_LIST], [python python3 python3.1 python3.2])
 AC_ARG_WITH([pythonpath],
 AC_HELP_STRING([--with-pythonpath=PATH],
   [specify an absolute path to python executable when automatic version check (incorrectly) fails]),